feat: Configurable MCP Server URL in Admin Settings (#76)

[AndriiPasternak31]

Summary

• Admin can now configure the MCP server URL in Settings (for production deployments proxied through nginx)
• API Keys page shows the configured URL in connection snippets (or auto-detects from hostname)
• Single endpoint with split auth: GET for any user, PUT/DELETE admin-only
• URL validation: must be http/https and end with /mcp

Changes

• src/backend/routers/settings.py — GET/PUT/DELETE /api/settings/mcp-url endpoints
• src/frontend/src/views/Settings.vue — MCP URL config section with badge, save/reset
• src/frontend/src/views/ApiKeys.vue — Fetch configured URL on mount
• tests/test_settings.py — 9 new tests (TestMcpUrlSettings)
• docs/memory/changelog.md — Change entry
• docs/memory/feature-flows/ — Updated platform-settings.md and api-keys-page.md

Test Plan

• New tests pass: pytest tests/test_settings.py::TestMcpUrlSettings -v
• Existing tests unaffected: pytest tests/test_settings.py -v
• Manual: Settings → enter custom URL → Save → API Keys shows it
• Manual: Settings → Reset → API Keys reverts to auto-detect
• Validation: invalid URLs rejected with clear error

Closes #76

Generated with Claude Code

[vybe]

This PR requires the following changes before merge:

• Add requirement entry to docs/memory/requirements.md (e.g., under section 5 Platform Settings or section 7 MCP Integration)
• Add GET/PUT/DELETE /api/settings/mcp-url endpoints to docs/memory/architecture.md settings API table

Code and tests look good — just need the documentation updates per Trinity methodology (new feature = changelog + requirements + architecture).

[vybe]

PR Validation: APPROVED (with rebase required)

Code review passed — the implementation is clean, well-tested, and fully documented. However, the branch has 101 merge conflicts with main due to fork divergence and can't be merged in its current state.

Required before merge

• Rebase onto current main to resolve conflicts

How to rebase

git remote add upstream https://github.com/abilityai/trinity.git
git fetch upstream
git rebase upstream/main
# Resolve any conflicts, then:
git push --force-with-lease

The actual feature changes (settings.py, ApiKeys.vue, Settings.vue, test_settings.py) are small and focused — most conflicts will be in files your branch didn't touch, so accepting the upstream version (git checkout --theirs <file>) should work for those.

Once rebased, this is ready to merge. The code, tests, docs, and security all look good.

[vybe]

Please rebase this branch onto main to resolve any conflicts and incorporate recent changes.

Once rebased, request re-review.

[vybe]

Validated via /validate-pr. Complete documentation (requirements, architecture, feature flows, changelog), 9 comprehensive tests, clean implementation following existing patterns.

[AndriiPasternak31]

Rebased onto main — mergeable: CLEAN. Conflict resolution summary:

Settings.vue — 4 conflict regions, all "both sides added adjacent new content" patterns (User Management section from ROLE-001 + my MCP URL section; usersList state + mcpUrlConfig state; serial loads + my parallel load; role/user functions + MCP URL functions). Union-merged: kept both sides with correct div closure for the template conflict. The loadSlackTransportStatus loader (new on upstream) was folded into the parallel Promise.all([...]) introduced by the simplify commit.

settings.py — single import-line conflict (upstream added Optional to typing, I added urlparse from urllib.parse). Kept both.

docs/memory/feature-flows.md — single row conflict on the Recent Updates table. Inserted the #76 row at its chronological position.

docs/archive/memory/changelog.md — resolved to upstream. The changelog was deprecated on main (7792127, git history is now the source of truth), so the b6e93b3 commit that polished the changelog entry became empty and was dropped during rebase.

Post-rebase doc fix (fb9a0ab) — the platform-settings.md table referenced Settings.vue lines 827-889 for the MCP URL section, computed against the old file. After rebase the section sits at lines 1089-1149; updated the reference. Did not touch other pre-existing stale line references in the same table (out of scope).

Final branch: 5 commits, no production behavior change vs the pre-rebase branch. Re-running /validate-pr should reproduce the previous APPROVED result.

[AndriiPasternak31]

Rebased again onto main (now at 65cdd91) — mergeable: CLEAN.

7 new upstream commits since the last rebase. One conflict on docs/memory/feature-flows.md: the previous rebase accidentally committed a stray <<<<<<< HEAD marker in commit 68c7de0; cleaned up that marker and union-merged the two new 2026-04-19 rows (#211, #378) above the existing Recent Updates list. #76 row still at its chronological 2026-03-25 position.

Five commits preserved; no code changes, docs-only tweaks. Ready for re-review.