rebrand: rename VoiceBox to TalkBox throughout codebase

- All 'voicebox'/'Voicebox'/'VOICEBOX' strings replaced with 'talkbox'/'TalkBox'/'TALKBOX'
- Port changed from 17493 to 17494 (avoids conflict with upstream VoiceBox)
- MCP tool namespace: voicebox.* -> talkbox.*
- App bundle ID: sh.voicebox.app -> com.talkbox.app
- Binary names: voicebox-server -> talkbox-server, voicebox-mcp -> talkbox-mcp
- Docker user/group: voicebox -> talkbox
- Database: voicebox.db -> talkbox.db
- Env vars: VOICEBOX_* -> TALKBOX_*
- Asset files renamed: voicebox-logo.* -> talkbox-logo.*, etc.
- External binaries in tauri.conf.json updated to talkbox-server/talkbox-mcp

.agents/skills/triage-prs/SKILL.md

@@ -30,7 +30,7 @@ This skill pairs with `draft-release-notes` and `release-bump`: triage first, th
 ```bash
 git worktree list  # check for stale ones first
 git worktree prune
-git worktree add ../voicebox-pr-review -b pr-review-<VERSION> main
+git worktree add ../talkbox-pr-review -b pr-review-<VERSION> main
 ```
 
 Keep the main worktree for release-prep work (changelog drafts, direct-to-main follow-ups). Keep the review worktree for `gh pr checkout` — each checkout moves HEAD to a contributor branch, which you don't want to do in the main worktree.
@@ -121,7 +121,7 @@ For each PR in the tier-1 / tier-2 list:
 
 **a. Checkout in the review worktree:**
 ```bash
-cd ../voicebox-pr-review
+cd ../talkbox-pr-review
 git checkout pr-review-<VERSION>  # reset to neutral base
 gh pr checkout <N>
 ```