fix: un-red main — dead import + app-bundle manifest re-pin (release 0.2.4 blocker)

[aarontrowbridge]

Problem — main is red in CI after #494/#497-era merges: fast fails typecheck (an extension entrypoint carries an import that is no longer used after the catalog removal), and app-bundle-gate fails its drift check (the devtools toggle fix #489 was hand-copied into the committed overlay without re-pinning the manifest, so the overlay no longer matches what the pinned fork tag would extract). Both failures predate the #306 merge and block any release cut from main.

Approach — two surgical fixes with zero content change: drop the dead import; and make the manifest honest by tagging the fork release lineage (v1.18.10-amicode.15 = the .14 pin + cherry-pick of the fork's devtools-fix commit, so extraction reproduces the current overlay byte-for-byte) and re-running the extractor against that tag. The fork's later work (solver banner, workspace engine, settings permissions) stays OUT of this sync — it belongs to its own coordinated extraction.

Acceptance Criteria

• Typecheck passes on main (the unused import is removed).
• The drift gate passes with the fork reachable: pins resolve, fresh extraction reproduces the manifest, and the committed overlay matches it.
• The overlay directory content is unchanged by this fix (manifest-only diff, plus the import line).
• Fork tag v1.18.10-amicode.15 and its release branch are pushed (the manifest's pin contract).

Source

Fix-forward for red main observed while cutting the 0.2.4 release (merge commit of #306 inherited both failures from #489/#497-era merges).

Notes

• Fork release branch: release/v1.18.10-amicode.15 (pin + cherry-pick of the fork's Pin the shipped Piccolo to the vetted 1.19 series #223 devtools fix — the exact two files that were hand-copied into the overlay).
• Verification on the fix branch: typecheck clean, drift gate PASS (full, fork present), extension suite 1206 passed / 5 skipped / 100 files.