v0.3.4 — prettier place_call card + readable notification/changes sur…

…faces

- frontend: redesign place_call tool card (phone icon chip, eyebrow +
  callee header, animated status pill, labelled field grid surfacing
  language/objective/duration/cost, typing indicator, transcript empty
  state); append-only place-call- scoped CSS.
- frontend: fix near-unreadable transparency on notification popups and
  the Changes rail — new --glass-bg-strong (0.92/0.95 alpha) applied to
  .toast/.notification-toast and .changes-rail, blur/glass preserved.
- bump version 0.3.3 -> 0.3.4 across Cargo.toml/tauri.conf.json/packaging.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fix(build): add gcc-c++ BuildRequires for esaxx-rs C++ link

After the rustls fix cleared openssl-sys, the COPR mock chroot failed at
link time with "cannot find -lstdc++". The bundled-embeddings stack
(fastembed -> tokenizers -> esaxx-rs) compiles esaxx.cpp via cc, which
emits -lstdc++. The minimal chroot has cmake/nasm but no C++ toolchain;
gcc-c++ provides the compiler and the libstdc++.so link target.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>