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_088.md

@@ -0,0 +1,38 @@
+# Task ID: 88
+
+**Title:** Rename proxyMode: filtered to proxyMode: proxy
+
+**Status:** cancelled
+
+**Dependencies:** 87 ✗
+
+**Priority:** low
+
+**Description:** Rename the existing proxyMode value 'filtered' to 'proxy' for clarity, with backwards compatibility for existing configs.
+
+**Details:**
+
+Update `src/db/prisma/schema.prisma`:
+
+```prisma
+enum ProxyMode {
+  direct
+  proxy  // renamed from 'filtered'
+}
+```
+
+Create migration that updates existing 'filtered' values to 'proxy':
+```sql
+UPDATE Project SET proxyMode = 'proxy' WHERE proxyMode = 'filtered';
+```
+
+Update all code references from 'filtered' to 'proxy':
+- `src/mcplocal/src/http/project-mcp-endpoint.ts`
+- `src/cli/src/commands/create.ts`
+- Documentation and help text
+
+For backwards compatibility in config files, add a normalization step that treats 'filtered' as 'proxy'.
+
+**Test Strategy:**
+
+Migration test: existing projects with proxyMode='filtered' are updated to 'proxy'. Config parsing test: both 'filtered' and 'proxy' values work. CLI test: help text shows 'proxy' not 'filtered'.