emrg: GUI packaged fix — whitelist conn-manager.js + gui-state.js + require-coverage guard

[argszero]

Summary

Fixes v0.2.21 packaged GUI startup crash (rant 2026-08-10T20:37:08, host-tested on Windows):

Uncaught Exception:
Error: Cannot find module './conn-manager'
Require stack:
- ...app.asar/main.js:25

Root cause: the GUI multi-session work (P2/P4) added emrg/gui/conn-manager.js and emrg/gui/gui-state.js, but electron-builder's files whitelist in package.json was never updated — same failure class as #612 (vendor/**). Both modules exist in the repo but were NOT packed into app.asar → packaged GUI crashes on require.

Changes:

1. emrg/gui/package.json — add conn-manager.js + gui-state.js to build.files whitelist.
2. emrg/gui/test/build-config.test.js — new guard: every require("./x") in main.js/preload.js must be covered by the files whitelist. This makes the entire class of "forgot to whitelist a new module" bugs fail CI at PR time (conn-manager.js / gui-state.js are exactly this pattern). Verified discriminating: removing conn-manager.js from the whitelist → the new test fails with a clear message.
3. Doc counts — GUI 178 → 179 (build-config 3→4) synced across README.md / README.cn.md / Agent.md (doc-count guard emrg: sync test counts to 484 + guard test against doc drift (recurs #426/#430/#510) #511).

Verification

• cd emrg/gui && npm test: 179/179 pass (was 178; +1 new guard test)
• Negative-state check: whitelist minus conn-manager.js → guard test FAILS (exit 1, names the missing module)
• uv run pytest tests/ -v: 681 pass (incl. test_doc_counts.py 3/3)
• import check + emrg --help: OK

Acceptance mapping

• Packaged GUI starts without Cannot find module './conn-manager' (files now packed)
• app.asar contains conn-manager.js (whitelist covers it; guard enforces)
• Multi-session works (connManager present in package)
• Source mode unchanged (no regression)
• CI packaging guard exists (require-coverage test prevents recurrence)

[argszero]

✅ LGTM — cycle

Verified (cycle 499):

• Root cause confirmed: main.js requires ./conn-manager and ./gui-state but electron-builder files whitelist lacked both → packaged GUI (v0.2.21 Windows) crashed with "Cannot find module './conn-manager'"
• Fix: both modules added to package.json build.files whitelist (+75/-10, 5 files)
• New guard test scans main.js/preload.js local requires vs whitelist — validated POSITIVE (4/4 pass on branch, incl. new test) and NEGATIVE (removing conn-manager.js from whitelist → test fails with actionable message listing the uncovered module)
• Docs synced: GUI 178→179 (build-config 3→4) in Agent.md/README.md/README.cn.md; Agent.md gains Terminology section (tool loop / round / evolution cycle)
• CI (test run 31389438040) SUCCESS — doc-count guard #511 satisfied

[argszero]

✅ LGTM — cycle. Verified: build.files whitelist now covers conn-manager.js + gui-state.js (both required by main.js:15-16); new require-coverage guard in build-config.test.js scans every main.js/preload.js local require and asserts whitelist coverage (negative-state proven — removing an entry makes the guard fail naming the module); doc counts 178→179 synced across README.md/README.cn.md/Agent.md; CI test green (run 31389438040).

[argszero]

✅ LGTM — cycle

Re-verified (cycle 500):

• Head 124c95d unchanged, mergeable (mergeState CLEAN)
• Root cause confirmed: main.js requires ./conn-manager + ./gui-state, whitelist lacked both → packaged crash; fix adds both + require-coverage guard test (pos/neg validated R499)
• Docs synced (GUI 179, three files) — doc-count guard #511 satisfied
• CI (test run 31389438040) still SUCCESS
• 3 consecutive LGTMs from different cycles (499, parallel, 500) — merge condition met