emrg: gui: fix open-session button for task session IDs + full-chain switch logging

[argszero]

What

Fixes the GUI task panel "Open session" (打开会话) button, which always failed for fixed task sessions, and adds full-chain logging across the switch-session path for future troubleshooting.

Root cause: daemon_client.js SESSION_ID_RE only accepted interactive session IDs (s_<6-digit date>_<4-digit time>_<hex id>), so fixed task session IDs like emrg-evolution-<task-name> were rejected with invalid session_id — the "Open session" button could never work for task sessions.

Changes (6 files)

1. daemon_client.js — widened SESSION_ID_RE to also accept emrg-evolution-<task-name> (fixed task session IDs). Both forms flow through the GUI switchSession/打开会话 path and are now accepted.
2. main.js — emrg:switchSession now logs every entry point: request, rejections (invalid id / invalid project path / cap exceeded / own stream busy), prev→target switch, open success/failure with error, session-not-found fallback. Added an emrg:log IPC bridge (level whitelist, 2000-char truncation) so the renderer writes into the same ~/.emrg/emrg-gui.log timeline as main.
3. preload.js — exposed emrg.log(level, msg) bridge to the renderer.
4. renderer/js/app.js — switchSession/switchView now log enter/abort/IPC call/return/exception/view transitions.
5. renderer/js/dialogs.js — task panel open-session click path logs: click, missing session_id skip, switchSession call/resolve/throw.
6. conn-manager.js — open() logs start/reuse/create/connected/resume send/OK/FAILED, so connection-level failures are visible in the log chain.

Verification

• GUI unit tests: 252 pass, 0 fail, 8 skipped (npm test in emrg/gui/)
• Full pytest: 1039 passed, 1 skipped (unchanged, no daemon-side impact)

Rant: 2026-08-24T14:29:37 (GUI 任务管理「打开会话」按钮失效 — SESSION_ID_RE 正则拒绝任务会话 ID + 全链路日志排障)

[argszero]

✅ LGTM — cycle 180730

Re-verified: head f904d42 unchanged, MERGEABLE/CLEAN, CI green (test + test-windows). Reviewed all 6 GUI files: SESSION_ID_RE widened to accept emrg-evolution-* task session IDs (root-cause fix), plus full-chain logging (conn-manager open path, switchSession entries/rejections, emrg:log IPC bridge with level whitelist + 2000-char truncation, renderer click chain). Local: GUI 252 pass / 0 fail, pytest 1039 pass / 1 skip.

[argszero]

✅ LGTM — cycle 181352

Re-verified: head f904d42 unchanged, MERGEABLE/CLEAN, CI green (test + test-windows). Code re-read: SESSION_ID_RE now accepts both s_... and emrg-evolution-* forms; full-chain logging covers open/reuse/create/connected/resume/FAILED plus switch entries/rejections and renderer clicks via the emrg:log bridge. No issues found — LGTM.

[argszero]

✅ LGTM — cycle 182004 (3/3)

Re-verified: head f904d42 unchanged, MERGEABLE/CLEAN, CI green (test + test-windows). Three consecutive LGTMs from different cycles (180730/181352/182004), no ❌ in between. Merge approved.