…points

- Rename mcp_server_configs.go → mcp.go
- Move routes from /chats/mcp-servers to /mcp/servers (adjacent to
  existing /mcp/http transport endpoint)
- Update SDK client paths to match new route prefix
- Add user-facing endpoints:
  - GET /mcp/servers/user — list enabled servers with per-user auth status
  - GET /mcp/servers/{id}/oauth2/connect — initiate OAuth2 flow (redirect)
  - GET /mcp/servers/{id}/oauth2/callback — exchange code for token, store
    per-user, close popup
  - DELETE /mcp/servers/{id}/oauth2/disconnect — revoke user's token

Route structure:
  /api/experimental/mcp/
    /servers/           — admin CRUD (GET, POST)
    /servers/user       — user list with auth status
    /servers/{id}/      — admin CRUD (PATCH, DELETE)
    /servers/{id}/tools — tool snapshot
    /servers/{id}/oauth2/connect    — start OAuth2
    /servers/{id}/oauth2/callback   — complete OAuth2
    /servers/{id}/oauth2/disconnect — revoke token
    /http               — MCP HTTP transport (existing)

The /servers/user endpoint was redundant — the main GET /servers/
endpoint already branched on admin vs non-admin. Merged the user
token lookup into the main handler so a single endpoint returns
configs + auth_connected status for the calling user.

- Add 8 test functions covering CRUD, non-admin visibility, auth_connected
  field, availability validation, slug uniqueness, tool snapshots, OAuth2
  disconnect, and per-chat MCP server ID persistence.
- Rename codersdk/mcpserverconfigs.go → codersdk/mcp.go to match coderd/mcp.go.
- Fix nil slice bug where omitted tool_allow_list/tool_deny_list in create
  requests would send NULL to NOT NULL columns.

Add rename entries in sqlc.yaml so generated Go types use
idiomatic casing (MCPServerConfig, MCPServerIDs, etc.) instead
of sqlc's default CamelCase (McpServerConfig, McpServerIds).

…eanup

- Add dbcrypt encrypt/decrypt wrappers for all MCP server methods:
  - MCPServerConfig: OAuth2ClientSecret, APIKeyValue, CustomHeaders
  - MCPServerUserToken: AccessToken, RefreshToken
  - 8 decrypt-only wrappers for Get* methods
  - 3 encrypt+decrypt wrappers for Insert/Update/Upsert methods
- Fix revive lint: split convertMCPServerConfig into two functions
  (convertMCPServerConfig + convertMCPServerConfigRedacted) instead
  of a single function with bool control flag
- Implement CleanupDeletedMCPServerIDsFromChats in dbauthz (was panic stub)
- Remove orphaned code from incomplete sed replacement
- Remove non-existent convertMCPServerConfigForRole references

…iciency

- Fix getMCPServerTools 500 for non-admin users: use AsSystemRestricted
  for both GetMCPServerConfigByID and GetActiveMCPServerToolSnapshot,
  and enforce Enabled check for non-admin callers.
- Fix OAuth2 state cookie Secure flag: use HTTPCookies.Apply() from
  deployment config instead of r.TLS != nil, matching the pattern in
  userauth.go. Fixes CSRF cookie not working behind TLS-terminating
  reverse proxies.
- Fix strings.Split on empty OAuth2Scopes producing [""] instead of
  []: guard with non-empty check before splitting.
- Add AuthConnected population to GET-by-ID handler, matching the
  list handler's token lookup logic.
- Remove omitempty from AuthConnected bool field so false is always
  serialized in JSON responses.
- Narrow CleanupDeletedMCPServerIDsFromChats WHERE clause to only
  update chats that actually reference deleted config IDs, avoiding
  unnecessary WAL writes.

The frozen tool snapshot table is premature without the refresh-tools
flow wired up. Tool filtering is handled by tool_allow_list and
tool_deny_list on mcp_server_configs, which is sufficient for the
initial implementation.

Removes:
- mcp_server_tool_snapshots table and its partial unique index
- GetActiveMCPServerToolSnapshot, InsertMCPServerToolSnapshot,
  DeactivateMCPServerToolSnapshots queries
- getMCPServerTools and refreshMCPServerTools handlers + routes
- MCPServerTool, MCPServerToolSnapshot SDK types + client method
- dbauthz/dbmetrics wrappers for removed queries
- TestMCPServerConfigsToolSnapshot test

- Fix revive if-return lint in dbcrypt helpers: return decryptField
  directly instead of redundant if-err-return-nil pattern.
- Fix timeout context used after t.Parallel: create per-subtest
  contexts in TestMCPServerConfigsAvailability.

…ransaction

- Use api.HTTPClient via context.WithValue(ctx, oauth2.HTTPClient, ...)
  for the OAuth2 token exchange instead of http.DefaultClient. This
  respects proxy settings and avoids SSRF with unrestricted client.
- Wrap the update handler's read-modify-write in api.Database.InTx
  so concurrent PATCHes don't silently clobber each other. Request
  parsing and custom header validation stay outside the transaction.

- Remove outdated comment claiming GET-by-ID endpoint doesn't exist.
- Make member get-by-ID assertions consistent with member list loop:
  assert all 7 redacted fields (OAuth2ClientID, OAuth2AuthURL,
  OAuth2TokenURL, OAuth2Scopes, APIKeyHeader, URL, Transport).
- Add missing OAuth2Scopes assertion to member list loop.

- Add comprehensive dbcrypt tests for all 11 MCP server methods:
  8 subtests for config encrypt/decrypt (Insert, Get*, Update) and
  3 subtests for user token encrypt/decrypt (Upsert, Get*). Each
  verifies plaintext on read and ciphertext in raw DB.
- Improve invalid MCP server ID error message to list which specific
  IDs are invalid, in both postChats and postChatMessages.
- Fix CleanupDeletedMCPServerIDsFromChats RBAC assertion to use
  ResourceChat (it modifies chats) instead of ResourceDeploymentConfig.

- Add //nolint:gosec directives for test credential constants.
- Fix context.Context parameter ordering (must be first) in
  requireMCPServerConfigRawEncrypted helper.
- Fix mangled const block and closing paren.