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_135.md

@@ -0,0 +1,27 @@
+# Task ID: 135
+
+**Title:** Backup and YAML kinds for new resources
+
+**Status:** pending
+
+**Dependencies:** 126, 128, 131, 133
+
+**Priority:** medium
+
+**Description:** Add new resources to BACKUP_KINDS, APPLY_ORDER, kindMap, and export/import loops
+
+**Details:**
+
+Update backup/apply infrastructure:
+1. Add 'Epic', 'EpicTask', 'Task', 'CodeRepo' to BACKUP_KINDS array
+2. Update APPLY_ORDER for correct dependency ordering (Epic before EpicTask before Task)
+3. Add to kindMap: { Epic: 'epics', EpicTask: 'epictasks', Task: 'tasks', CodeRepo: 'repos' }
+4. Update serializeResource for each new kind
+5. Update kindFromSegment in main.ts import handler
+6. Update importResource for create/update logic per kind
+7. Update deleteResource for each kind
+8. Fix existing gap: add 'skill' to importResource/deleteResource if missing
+
+**Test Strategy:**
+
+Integration tests: test backup exports all new resource types, test apply imports Epic→EpicTask→Task in correct order, test round-trip export→import preserves data.