feat: add the TechLog Studio asset library route and screen

Adds TECH_LOG_STUDIO_ASSETS (/studio/assets) as a route reachable but
excluded from primary Studio navigation (navigationLabel/navigationOrder
null), plus the AssetLibrary screen that lists assets, shows usage, and
lets an operator archive or hard-delete one. canHardDelete() is a pure
gate mirroring the server's ASSET_IN_USE rule so the screen never offers
an action the server would refuse.

Adding a 28th route also required updating the route-scoped CI
accessibility-evidence gate (FE-GATE-009 in config/ci/gates.json, plus
its authority-baseline counts and shape digest in
scripts/contracts/ci-gates.ts) and the Vite route-to-chunk map that
scripts/generate-build-manifest.ts depends on, or test:unit and the
production build both fail. See task-11-report.md for the full
breakdown.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/unit/task3-selective-integration.test.ts

@@ -183,11 +183,12 @@ describe("selective Task 3 contract closure", () => {
     const canonical = await loadCiGateContract(process.cwd());
     // Template merge. The template added one gate and one command to the
     // product's 26/81; the artifact set is the product's 126 plus the
-    // template's 2.
+    // template's 2. Task 11 added TECH_LOG_STUDIO_ASSETS's manual
+    // accessibility evidence, bringing the total to 129.
     expect(canonical.gates).toHaveLength(27);
     expect(canonical.commands).toHaveLength(82);
     expect(canonical.gates.reduce((sum, gate) => sum + gate.commandIds.length, 0)).toBe(94);
-    expect(canonical.artifacts).toHaveLength(128);
+    expect(canonical.artifacts).toHaveLength(129);
     expect(canonical.stages).toHaveLength(5);
     expect(canonical.retention.classes).toHaveLength(5);