merge: AgentProject membership — the junction is now load-bearing

Merges feat/agent-project-membership (task 166/152). An agent can finally join
many projects: membership routes, per-membership role and optional brain
override, chat resolving context from the membership, and CLI attach-agent /
detach-agent / get memberships. The legacy Agent.projectId fallback is kept for
this release as the schema comment promises.

Conflict resolved in main.ts: that branch added its RBAC case to
mapUrlToPermission inline, while this branch had extracted the function to
middleware/url-permission.ts so it could be tested. Kept the extraction and
ported the case into it — joining a team is `edit:agents:<name>`, not
`create:agents`, which is the authority to mint a whole agent.

Also fixes something the extraction makes possible. security.test.ts contained a
hand-copied reproduction of mapUrlToPermission, because main.ts self-invokes
main() and nothing in it was importable. A security test asserting against a
copy stops testing the system the moment the real one changes, and this copy had
already drifted. It now imports the real function; all 18 assertions still pass,
against the code that actually runs.

Local: build clean, workspace 2550 passed, lint unchanged at 794 errors.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4wNHWf7xSwnZCWpJcyv9p

.taskmaster/tasks/task_037.md

@@ -0,0 +1,36 @@
+# Task ID: 37
+
+**Title:** Add priority, summary, chapters, and linkTarget fields to Prompt schema
+
+**Status:** done
+
+**Dependencies:** None
+
+**Priority:** high
+
+**Description:** Extend the Prisma schema for the Prompt model to include priority (integer 1-10, default 5), summary (nullable string), chapters (nullable JSON array), and linkTarget (nullable string for prompt links).
+
+**Details:**
+
+1. Update `/src/db/prisma/schema.prisma` to add fields to the Prompt model:
+   - `priority Int @default(5)` with check constraint 1-10
+   - `summary String? @db.Text`
+   - `chapters Json?` (stored as JSON array of strings)
+   - `linkTarget String?` (format: `project/server:resource-uri`)
+
+2. Create Prisma migration:
+   ```bash
+   pnpm --filter db exec prisma migrate dev --name add-prompt-priority-summary-chapters-link
+   ```
+
+3. Update TypeScript types in shared package to reflect new fields
+
+4. Add validation for priority range (1-10) at the database level if possible, otherwise enforce in application layer
+
+**Test Strategy:**
+
+- Unit test: Verify migration creates columns with correct types and defaults
+- Unit test: Verify priority default is 5
+- Unit test: Verify nullable fields accept null
+- Unit test: Verify chapters stores/retrieves JSON arrays correctly
+- Integration test: Create prompt with all new fields, retrieve and verify values