Add GetSymbolChildren to Registry for enhanced hover

This adds a new method to retrieve first-level children of a symbol
(fields, methods, etc.) from the prefix tree. For methods, it also
includes their parameter children.

This enables IDEs to display richer hover information showing class
structure with fields and method signatures.

Changes:
- Add SymbolChild struct to model
- Add GetSymbolChildren to PartialIndex interface and implementation
- Add GetSymbolChildren to Registry interface and implementation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

feat(scip-lib): Add symbol visited callback (#51)

## Description
**What**:
- Add a callback that fires for every non-local symbol during index
scanning.
- Expose it through both the partial loader and registry layers.

**Why**:
- Allow consumers to build auxiliary data structures (e.g., search
indices) from all symbols as SCIP files are scanned, without requiring a
second pass over the file.


## Type of Change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [x] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [x] Tests

## Testing

- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [ ] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing: N/A
- Project(s) tested against: N/A
- Specific features/scenarios verified: N/A

## Checklist

- [x] My code follows the existing code style and conventions
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] I have updated BUILD.bazel files if I added new source files
- [x] My changes generate no new warnings
- [ ] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

N/A

## Related Issues

N/A

## Additional Notes

This is a breaking interface change; any external implementations of
`PartialIndex` or `Registry` will need to add the new method. The
callback mirrors the existing `SetDocumentLoadedCallback` pattern.

Add additonal mapper for scip symbol kind to protocol symbol (#49)

## Description

We observed that the abstract method are not correctly identified in
scip lsp
despite the type was correctly produced by indexer.

This was due to missing mapping for the types supported which resulted
into null type being sent out.

Here in this change we add missing types in the mapper.
This would ensure we are able to correctly identify the types in the lsp
client.

## Type of Change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [x] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [ ] Tests

## Testing

- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [ ] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing:
- Project(s) tested against:
- Specific features/scenarios verified:

## Checklist

- [x] My code follows the existing code style and conventions
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] I have updated BUILD.bazel files if I added new source files
- [ ] My changes generate no new warnings
- [ ] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

Include any relevant screenshots, logs, or output that demonstrates the
changes.

## Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

## Additional Notes

Any additional information that reviewers should know about this PR.

Add goto Implementation controller (#45)

## Description

This PR adds the new feature `goto Implementation` to the SCIP
controller using reverse implementors index method(ref:
#23)
Tested in company's IDE, ensure the functionality works fine:


https://github.com/user-attachments/assets/d1c21114-c099-49e9-90c0-fd14059dd446



## Type of Change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [x] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [ ] Tests

## Testing

- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [x] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing:
- Project(s) tested against:
- Specific features/scenarios verified:

## Checklist

- [x] My code follows the existing code style and conventions
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] I have updated BUILD.bazel files if I added new source files
- [x] My changes generate no new warnings
- [x] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

Include any relevant screenshots, logs, or output that demonstrates the
changes.

## Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

## Additional Notes

Any additional information that reviewers should know about this PR.

refactor(scip): separate out files in mapper that depends on proto to…

… another directory (#31)

## Description
Move all functions under `src/ulsp/mapper` that touch proto code into a
separate sub-package, `src/ulsp/mapper/idl`.
This way:
`src/ulsp/mapper` only contains logic for LSP, JSON-RPC, and general
mapping.
`src/ulsp/mapper/idl` contains the parts that translate between internal
models and protobuf messages.
When a controller imports mapper, no proto code is compiled in.
Only code that explicitly imports mapper/idl will depend on the
generated .pb.go files.
So that it won't cause `proto: duplicate proto type registered:` error
log when importing `github.com/uber/scip-lsp/src/ulsp/controller/scip`
due to importing two versions of the same proto file that may conflict
with each other

Also checked build graph:
```
$ bazel query "somepath(//src/ulsp/controller/scip:go_default_library, //idl/...)" 
INFO: Empty results
```
## Type of Change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [x] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [x] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [ ] Tests

## Testing

- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [x] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing:
- Project(s) tested against:
- Specific features/scenarios verified:

## Checklist

- [x] My code follows the existing code style and conventions
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] I have updated BUILD.bazel files if I added new source files
- [ ] My changes generate no new warnings
- [ ] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

Include any relevant screenshots, logs, or output that demonstrates the
changes.

## Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

## Additional Notes

Any additional information that reviewers should know about this PR.

downgrade testify in go mod (#30)

## Description

Downgrade github.com/stretchr/testify to v1.10.0 so that when importing
scip-lsp in other repo there will not cause compatibility issue.

## Type of Change

- [X] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [ ] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [x] Tests

## Testing

- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [x] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing:
- Project(s) tested against:
- Specific features/scenarios verified:

## Checklist

- [ ] My code follows the existing code style and conventions
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] I have updated BUILD.bazel files if I added new source files
- [ ] My changes generate no new warnings
- [ ] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

Include any relevant screenshots, logs, or output that demonstrates the
changes.

## Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

## Additional Notes

Any additional information that reviewers should know about this PR.

fixup! tidy go deps (#26)

## Description

Updates the go dependecies to get rid of some stale items; Move to
tally/v4 for build errors.

## Type of Change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update
- [ ] Refactoring (no functional changes)
- [ ] Performance improvement
- [ ] Test improvement

## Component(s) Affected

- [x] Language Server (ULSP)
- [ ] SCIP Generation (Python utilities)
- [ ] VS Code/Cursor Extension
- [ ] Java Aggregator
- [ ] Build System (Bazel)
- [ ] Documentation
- [ ] Tests

## Testing

- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes (`bazel
test //...`)
- [x] I have tested this manually with a real project

### Manual Testing Details

Describe how you tested these changes:
- IDE used for testing:
- Project(s) tested against:
- Specific features/scenarios verified:

## Checklist

- [ ] My code follows the existing code style and conventions
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] I have updated BUILD.bazel files if I added new source files
- [ ] My changes generate no new warnings
- [ ] Any dependent changes have been merged and published

## Screenshots/Logs (if applicable)

Include any relevant screenshots, logs, or output that demonstrates the
changes.

## Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

## Additional Notes

Any additional information that reviewers should know about this PR.