chore: remove dead code (59 unused files + ~125 unused exports) (#1835)

* chore: remove dead/unreferenced files across ui, vscode

Remove 59 unused source files (components, hooks, lib utils, stores,
barrels, and orphaned vscode github modules) that are not imported by
any entry-reachable code. Also drop a stale test mock for the removed
execCommands module.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* refactor: remove unused exported symbols (types, functions, consts, hooks)

Remove exported symbols whose identifier is referenced nowhere in the
repository (verified via repo-wide search), across ui types/contracts,
lib utilities, sync layer, stores, and components. Also drop the few
imports/private helpers orphaned by these removals.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* refactor: remove more unused exports (desktop, shortcuts, worktree, vscode)

Continue removing repo-wide unreferenced exported functions, consts and
types across lib/desktop, shortcuts, worktreeSessionCreator, sync, and
vscode gitService, with cascading orphaned helpers/imports cleaned up.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* chore: add dead-code cleanup tooling

* refactor: checkpoint dead-code cleanup

* refactor: remove dead-code suppressions

---------

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

package.json

@@ -51,6 +51,7 @@
     "vscode:package": "bun run --cwd packages/vscode package",
     "vscode:type-check": "bun run --cwd packages/vscode type-check",
     "docs:validate": "node scripts/docs/validate-docs.mjs",
+    "dead-code": "bunx knip --no-exit-code --include files,exports,nsExports,types,nsTypes,enumMembers,namespaceMembers,duplicates",
     "doctor": "node scripts/react-doctor.mjs",
     "icons:sprite": "node scripts/generate-file-type-sprite.mjs",
     "icons:generate": "bun run scripts/generate-icon-sprite.mjs",