v0.5.0: Add jot stats command for journal snapshots

v0.4.0: Add jot tag command for tag management

fix: Nil-pointer panics, search filters, and code quality improvements

- Fix nil-pointer panic in `new` when os.Stat fails on temp file
- Fix nil-pointer panic in `show` when os.Stdout.Stat fails
- Remove duplicate --force flag in `rm` (cobra conflict with --yes alias)
- Handle yaml.Marshal error defensively in entry.ToMarkdown
- Allow `done` on any entry type, not just tasks
- Add --status and --priority filters to `search` command
- Support partial slug matching in `lint` via ResolveSlug
- Rename --tag to --tags across list and search for consistency
- Fix variable shadowing in lint.go error loop
- Fix gofmt formatting in config_test.go
- Add tests for done-on-non-tasks, search filters, lint partial slugs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Simplify and clean up codebase for consistency and maintainability

- Replace manual bubble sorts with sort.Slice in list and tasks commands
- Extract shared truncateSlug/truncateTitle helpers to eliminate duplication
- Remove unused mustGetStore function and dead imports from root.go
- Replace manual status validation loop with entry.Contains()
- Define named entryImporter interface to replace 3 inline declarations
- Export Contains helper from entry package for cross-package reuse
- Simplify path manipulation in slug.go with strings.TrimSuffix
- Clean up parsePositiveInt signature to idiomatic (int, error) return

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

v0.1.0 - Initial feature-complete release

Features:
- Full-text search with jot list --search
- Due date filtering and relative date support
- Partial slug matching with interactive selection
- Compact table output with verbose option
- Simplified CLI flags (--json, --table, --markdown)

Test coverage: store 85.9%, entry 80.9%, config 67.0%