docs(6204): shipped instruction text describes the product, not this instance's records

MCP tool docstrings and comments, the server's orientation notes, the plugin
skills, every hook script and the plugin README/PACKAGING drop record ids,
milestone numbers, dates and incident stories, and state each non-obvious why
as a present-tense fact. History stays in the task logs.

Corrections found on the way:
- plugin README/PACKAGING said every hook is a GET; moment, rule-opened and
  reply-rules POST, so the plugin's key needs write scope. Both now say so,
  name Settings -> MCP Access, and list every wired hook and endpoint.
- the contract-change hint printed "(lesson #4207)", this instance's record,
  to every install. It no longer cites a record.
- tasks.py claimed there is no delete_task; there is.
- rulebooks.py cited delete_event and a design spec that no longer exist.
- scribe_after_write.sh carried an always-empty etag_q; removed.
- test_write_path_trigger pinned "| tac | scribe_defs | head -1", text that
  existed only in a comment about the old code; it now pins the real tail -1
  pipeline.
- docs/development.md: CI runs on Gitea Actions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugin/hooks/scribe_session_end.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Scribe — release this session's task claims as it ends (milestone 381 step 4).
+# Scribe — release this session's task claims as it ends.
 #
 # A claim records a session's attention, and a session that ends has none left
 # to give. This is the mechanical half of the hand-off: it needs nothing from
@@ -31,8 +31,8 @@ event_flat=$(printf '%s' "$event" | scribe_json_flat)
 session_id=$(scribe_json_pick "$event_flat" '.session_id')
 [ -n "$session_id" ] || exit 0
 
-# The moment arm's per-session files (its tool cache and the acts ledger,
-# milestone 458) describe a session that is over, on any exit — a clear
+# The moment arm's per-session files (its tool cache and the acts ledger)
+# describe a session that is over, on any exit — a clear
 # included, since the next conversation is a new session id.
 safe_sid=$(printf '%s' "$session_id" | tr -c 'A-Za-z0-9._-' '_')
 rm -f "${TMPDIR:-/tmp}/scribe-moment/${safe_sid}".* 2>/dev/null || true