feat(discord): writes on write-marked roots, web fetch and search, held prompts (#1509)

Row 23. write_file and edit_file for roots marked write: true under the
same fence as reads; web_fetch (https only, public addresses, pinned
connection, capped body) and web_search through SearXNG; extension
renamed to tools.mjs. Engine holds a prompt while pi is busy and sends
it as its own run, so a second message mid-turn no longer folds into
the first (live defect). fake-pi models the real follow-up folding.

Suite 52/52, node tests 129. rev-code-02 APPROVED round 3, comment
26362, tree dbd2ce9a. Records: QUEUE rows 23-24, CURRENT, BUILD-LOG
phase, SESSIONS, row 24 brief (git verbs, D5-D7 ruled).

Co-Authored-By: Claude Fable 5.1 <[email protected]>

docs/plans/CURRENT.md

@@ -368,3 +368,7 @@ git history + Gitea issues.
 - 2026-09-13 — Discord connector iteration 2 (#1509, QUEUE row 17): systemd user service `mosaic-discord@<binding>` with a supervised run that clears a dead lock and never retries a brake (exit 3). Sage seat now runs under systemd, not tmux. Next: control board row.
 - 2026-09-13 — Discord connector iterations 4 and 5 (#1509, QUEUE rows 19–20): `reload` verb and `systemctl --user reload` apply channels, users, limits and guildName to the running connector, fixed keys refused, attempts journaled in `reloads.jsonl`; per-user channel allowlist; Carmen enrolled live by a reload at 00:03 UTC (all listed rooms except #sage-admin). Suite 41/41, 101 node tests. Commit caaef941 plus records. Row 18 (board row) is darkwing's by Jason's ruling.
 - 2026-09-14 — Discord connector iteration 6 (#1509, QUEUE row 21): read-only tools through a Mosaic pi extension confined to declared roots (Jason's R1–R7: repo `docs/` and `agents/sage/`, every listed user including Carmen, 8 calls a message, 400 lines a read, 256 KiB a file, refusals said plainly, `tools` a fixed key). rev-code-02 approved round 2 (26276). Suite 41 → 48, node tests 101 → 116. Next: live check in #sage-admin, then attachments.
+- 2026-09-16 — Discord Sage ops (#1509), Jason's word: every text channel of Shared Signals added in mention mode (#sage-admin stays open, Carmen's one-channel allowlist unchanged), and `/mnt/storage/src/shared-signals` added as a third read-only root. Threads had been silent because their parent #ideas was unlisted, not a code defect. Private binding only; check passed, service restarted; receipt in the Sage evidence dir. New channels created later need adding by reload.
+- 2026-09-16 (coordinator, #1509 row 23): part 1 writes built: `write_file`/`edit_file` for roots marked `write: true`, temp file plus rename, same fences as reads plus parent-must-exist, no dot paths, no credential shapes; `enabledToolNames` drives `--tools`, the extension and the check line; suite 49/49. Pinned for rev-code-02 round 1 (tree in the #1509 comment). Live finding: after the prompt fix Sage still repeated "ruling Q16" and "two read-only folders" with zero tool calls, because pi resumed the session that held every earlier refusal; the old session file was archived to the sage evidence dir and the service restarted with a fresh session. Writes and web reach Sage only after row 23 lands in the binding.
+- 2026-09-16 (coordinator, #1509 row 23): part 2 web built: `src/web.mjs` with `webFetch` (https only, public addresses only, connection pinned to the vetted address, three re-vetted redirects, 1 MiB cap, html to text) and `webSearch` (SearXNG json, ten results); enabled only when the binding `tools.web` key is set. The full-suite hang was a race in `tests/engine.test.mjs` (busy asserted before `agent_settled`, fake pi never stopped); the test now waits for the settle and stops in `finally`. Suite 52/52, node 128. Round 2 pinned for rev-code-02 (comment 26358, aggregate 287af5da, tree 1721584c). Next: verdict, local commit of my 17 paths only, then SearXNG container on 127.0.0.1:8888 and the live check.
+- 2026-09-16 (coordinator, #1509 row 23): part 3 live: SearXNG container `mosaic-searxng` (image searxng/searxng:latest, settings in the data root, formats html and json, limiter off) on 127.0.0.1:8888; binding `tools.web` added (backup in the sage evidence dir); check ok; service restarted. Jason's first turn in #sage-admin searched, fetched who.is, listed the folder and wrote `vault/Businesses/naming.md`. Defect seen in the same exchange: his second message during the turn went to pi as a follow-up, pi folded it into the same run, the first answer was never posted and the second failed as settled-without-turn. Fixed in `engine-pi.mjs` (held prompts, one run each), fake pi now models real follow-up semantics, suite 52/52 node 129, round 3 pinned (comment 26361, aggregate e30c2319, tree dbd2ce9a), service restarted with the fix. Row 24 rulings: D5 seat identity with `[email protected]`, D6 push every commit (Jason: not pushing means stale data), D7 rev-code-02.