Hardening + collaboration features from full app review

Security and robustness (backend):
- Strict CSP (was null); confine read_file/launch_file/ue_log to the client root
- p4 trust without -f: surface fingerprint CHANGES instead of auto-accepting (MITM)
- stdin=null by default + non-interactive P4EDITOR so terminal commands never hang
- 64 MB read caps on read_depot/read_file/print_depot (no OOM on huge .uasset/.pak)
- Recover from mutex poisoning instead of crashing every later p4 call
- Decode p4 output as UTF-8 then cp1251 (Cyrillic paths no longer corrupt)
- p4_changes never deletes changelists that hold shelved files
- Validate changelist number in p4_undo_change

Bug fixes (frontend):
- Focus-refresh preserves the checkbox selection (never re-checks deselected files)
- Staleness guards on refresh/describe/AI-summary/user-groups (no cross-selection races)
- Real F5/Ctrl+R/G/S/B handlers; match e.code so Ctrl+backquote works on RU layout
- Confirm dialog no longer fires on a stray global Enter
- Panel/dock/history drags end on window blur (no stuck resize)
- Commit draft clears on Submit only if unchanged since committing
- Summary/IDE buttons gated to real source files (not .pak/.dll/binaries)

New features:
- Exclusive lock/unlock plus held-by/locked-by indicators (p4 opened -a)
- Shelve/unshelve/delete-shelf on pending changelists
- Resolve UI (auto-merge / accept yours / accept theirs, per file or all) + banner
- Diff a history revision against the previous one; blame/annotate view
- Depot file search (Tools -> Search depot)
- Move opened files between pending changelists
- New-submit toasts from teammates + offline banner with auto-reconnect

Also: bake OpenRouter key at build time (git-ignored), drop AI settings UI,
IDE picker (detect installed editors), AI replies in the UI language,
persistent code summaries, metadata/CSP polish.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src-tauri/Cargo.lock

@@ -874,6 +874,15 @@ version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ef6b89e5b37196644d8796de5268852ff179b44e96276cf4290264843743bb7"
 
+[[package]]
+name = "encoding_rs"
+version = "0.8.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75030f3c4f45dafd7586dd6780965a8c7e8e285a5ecb86713e63a79c5b2766f3"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "endi"
 version = "1.1.1"
@@ -953,6 +962,7 @@ dependencies = [
 name = "exbyte-depot"
 version = "0.2.2"
 dependencies = [
+ "encoding_rs",
  "serde",
  "serde_json",
  "tauri",