fix(build,docs): dependency preflight before the build wipes dist, docs drift for 1.40.0

- scripts/build.mjs resolves exceljs/dist/exceljs.min.js and fflate first,
  before tsc and before rm -rf dist/web/public. A tree whose node_modules
  predate those devDependencies (pulled but never ran npm install) used to
  fail in prepare-spreadsheet-assets.mjs with the live dist assets already
  deleted, so the running server served an index.html whose hashed files
  were gone. It now exits 1 with "run `npm install` first", nothing touched.
  test/spreadsheet-assets.test.ts pins the order, that the list covers every
  require.resolve in the prepare script, and runs a relocated copy of the
  build to prove the exit and message.
- CLAUDE.md: the header visibility rule's stock desktop default now lists
  Tiles (1180px and wider), which ships ON on desktop.
- docs/wiki/Agent-CLIs.md: "Before 1.36.0" becomes "Before 1.40.0" (four
  places); 1.36.0 never ships.
- docs/wiki/Home.md: the "Everything in the manual" index lists Tile Grid
  and Custom Model Endpoints, matching the sidebar. test/wiki-home-index
  fails when a sidebar page is missing from that index.
- docs/wiki/Tile-Grid.md: the Tiles default is off on tablets too since the
  touch-primary default landed, not only on phones.
- docs/browser-testing-guide.md: the fixed port table and new WebServer(PORT)
  snippet give way to the port-0 pattern (new WebServer(0, false, true),
  server.boundPort) that test/test-ports-guard.test.ts enforces; the
  examples that opened localhost:3000, the live instance, use BASE_URL.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/wiki/Agent-CLIs.md

@@ -124,7 +124,7 @@ environment is injected through socket-scoped `tmux setenv` rather than the comm
 Working and idle come from the screen: while a turn runs, OpenCode draws a small spinner at
 the start of its footer (`⬝■■■■■■⬝  esc interrupt`), and Codeman reads that to tell a working
 session from an idle one. A pending permission prompt shows as idle, since it is waiting on
-you. Before 1.36.0 an OpenCode session that had run a tool showed as working for good.
+you. Before 1.40.0 an OpenCode session that had run a tool showed as working for good.
 
 Integration detail: [`docs/opencode-integration.md`](https://github.com/Ark0N/Codeman/blob/master/docs/opencode-integration.md).
 
@@ -164,7 +164,7 @@ only the CLI you spawned yourself.
 
 Working and idle come from the screen: while a turn runs, Gemini CLI draws a spinner line
 (`⠦ Thinking... (esc to cancel, 6s)`) above its composer, and Codeman reads that. A tool
-confirmation that waits for you shows as idle. Before 1.36.0 a Gemini session showed as
+confirmation that waits for you shows as idle. Before 1.40.0 a Gemini session showed as
 working for good after its first turn.
 
 ### Antigravity
@@ -190,7 +190,7 @@ Pi needs the opposite instincts from every other CLI here.
   once. They stay out.
 - **Work detection reads Pi's composer rule.** Pi has no prompt glyph; while a turn runs it
   puts a spinner into the rule above the composer (`── ⠏ Working ───`), and Codeman reads
-  that to tell working from idle. Before 1.36.0 a Pi session that had started a turn showed
+  that to tell working from idle. Before 1.40.0 a Pi session that had started a turn showed
   as working for good.
 
 Guide: [`docs/pi-integration.md`](https://github.com/Ark0N/Codeman/blob/master/docs/pi-integration.md).
@@ -246,7 +246,7 @@ flag from Codeman; change that in OMP's own config, not here.
 
 OMP conversations appear in Past Sessions and can be resumed, and a respawn continues the
 same conversation with `--continue`. Codeman tells working from idle by reading OMP's status
-bar, where a spinner and the elapsed time replace the `π` while a turn runs. Before 1.36.0
+bar, where a spinner and the elapsed time replace the `π` while a turn runs. Before 1.40.0
 an OMP session that had started a turn showed as working for good.
 
 Guide: [`docs/omp-integration.md`](https://github.com/Ark0N/Codeman/blob/master/docs/omp-integration.md).

docs/wiki/Home.md

@@ -62,7 +62,9 @@ codeman web    # then open http://localhost:3000
 | Page                                       | What it answers                                            |
 | ------------------------------------------ | ---------------------------------------------------------- |
 | [The Dashboard](The-Dashboard)             | What is the UI telling me?                                 |
+| [Tile Grid](Tile-Grid)                     | How do I watch and drive several sessions side by side?    |
 | [Agent CLIs](Agent-CLIs)                   | Which agent should this session run, and how do I set it up? |
+| [Custom Model Endpoints](Custom-Model-Endpoints) | How do I point a session at my own OpenAI-compatible endpoint? |
 | [Working With Files](Working-With-Files)   | How do I read, edit, and attach files?                     |
 | [Input And Voice](Input-And-Voice)         | How do I talk to an agent, including by voice?             |
 | [Mobile Guide](Mobile-Guide)               | How well does this work on a phone?                        |

docs/wiki/Tile-Grid.md

@@ -10,7 +10,8 @@ never offered in a popped-out session window.
 ## Turning it on
 
 **App Settings → Header & Panels → Tiles.** This is a per-device setting, on by default
-everywhere except phones, and the button only appears in a window at least 1180px wide.
+on desktops and laptops and off on phones and tablets, and the button only appears in a
+window at least 1180px wide.
 It shows a **Tiles** button in the header, beside Split, and enables `Ctrl+Shift+G`.
 
 ## Opening a grid