feat(mcp): add uninstall + --check + README section for MCP pipeline

Three coupled additions close the MCP pipeline thread.

mcp/install.py grew --uninstall and --check modes via argparse. The
default install behavior is unchanged.

--uninstall iterates over servers.json and runs `claude mcp remove
<name> -s user` for each, skipping anything not registered. Idempotent.

--check is the dry-run drift report. For each server, classify as ok
(in both servers.json and `claude mcp list`), MISSING (configured but
not registered), or EXTRA (registered but not in servers.json). Exit
non-zero only on MISSING since EXTRA entries are often deliberate (the
claude.ai web servers register out-of-band). Smoke test against the
live config: 9 ok, 0 missing, 3 EXTRA, exit 0.

Two new Makefile targets:
- make uninstall-mcp invokes the --uninstall mode.
- make check-mcp invokes the --check mode.

README.org gained an MCP section under Two install modes covering all
three targets, the OAuth-token-on-disk story, and a pointer to
mcp/README.org for the full pipeline.

Closes TODO #7 (uninstall + --check) and TODO #8 (README MCP section).

1 files changed, 29 insertions, 0 deletions

diff --git a/README.org b/README.org
index 91e9804..067a2a1 100644
--- a/README.org
+++ b/README.org
@@ -49,6 +49,35 @@ What gets installed:
 The install is re-runnable. Running it again refreshes files in place; personal
 tweaks live in =.claude/settings.local.json= and are not touched.
 
+** MCP servers (user scope)
+
+Registers MCP servers globally (=user= scope) so every Claude Code project
+sees them. Reads structure from =mcp/servers.json= (placeholders =${VAR}=),
+decrypts secrets from =mcp/secrets.env.gpg= via gpg-agent, expands the
+placeholders, then registers anything not already present in
+=claude mcp list=. Idempotent — re-running is safe.
+
+#+begin_src bash
+make install-mcp     # decrypt + register everything in servers.json
+make uninstall-mcp   # remove every server listed in servers.json
+make check-mcp       # dry-run drift report (no decryption, no writes)
+#+end_src
+
+=check-mcp= classifies each server as =ok= (in both), =MISSING= (configured
+but not registered — run =install-mcp=), or =EXTRA= (registered but not
+configured — usually intentional manual additions like the claude.ai web
+servers). Exit code is non-zero only on =MISSING=, since =EXTRA= entries
+are often deliberate.
+
+What lands on disk during =install-mcp=:
+- =mcp/gcp-oauth.keys.json= (mode 600) — extracted for google-calendar-mcp
+- =~/.config/google-docs-mcp/{personal,work}/token.json= (mode 600) —
+  per-profile OAuth tokens for =@a-bonus/google-docs-mcp=
+
+Secrets never touch disk in plain form outside the OAuth artifacts above.
+The =.gpg= file is the source of truth; rotate via =gpg --edit-key= and
+re-encrypt. See [[file:mcp/README.org][mcp/README.org]] for the full pipeline.
+
 * Available languages
 
 | Language | Path             | Notes                                        |