perf: optimize session loading and desktop startup (#2545)

* perf: optimize session loading and startup

* fix(chat): stabilize history prepend virtualization

* perf: unblock first session open from startup network contention

Opening the first session after app start waited seconds for its message
fetch. Three independent contributors, each measured via CDP network
capture and Chromium net-log against the packaged desktop app:

- The active-session watchdog fired an uncapped per-directory status poll
  and child-session discovery burst at startup, and other subsystems
  (git checks, global session pages, command/skill discovery) fanned out
  alongside it, saturating the browser's ~6 HTTP/1.1 sockets per origin.
  Add a shared background-network gate (concurrency 3) and route the
  watchdog, poll-shaped git reads (also priority: low), global session
  pages, command/skill loads, and the background update check through it.

- The packaged renderer is cross-origin to the loopback backend, so every
  API call needs a CORS preflight; a few slow OpenCode-proxied requests
  held the whole pool while preflights and interactive traffic queued
  behind them. Lift Chromium's per-host connection cap for loopback via
  ignore-connections-limit in the Electron shell.

- OpenCode initializes each directory lazily on its first request, so the
  first click paid that cost interactively. Warm the last-used directory
  and the three most recently opened projects right after OpenCode
  readiness, sequentially and best-effort, overlapping UI startup.

Validation: new background-network tests, lifecycle warmup test, focused
store/sync tests, UI type-check and lint, dead-code report, node --check
plus electron type-check/lint, and CDP first-open measurements on the
packaged app (message fetch socket queue 5.4s -> 0.03s).

* fix(ui): keep interactive git reads out of background queue

---------

Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/web/server/lib/opencode/DOCUMENTATION.md

@@ -10,7 +10,7 @@ This module provides OpenCode server integration utilities for the web server ru
 - `packages/web/server/lib/opencode/cli-options.js`: CLI/environment option parsing for server startup arguments.
 - `packages/web/server/lib/opencode/cli-entry-runtime.js`: CLI entrypoint runtime that detects direct execution, parses CLI options, and starts server bootstrap.
 - `packages/web/server/lib/opencode/routes.js`: OpenCode/provider settings and auth-related route registration.
-- `packages/web/server/lib/opencode/lifecycle.js`: OpenCode process lifecycle runtime (startup, restart, readiness, health monitoring).
+- `packages/web/server/lib/opencode/lifecycle.js`: OpenCode process lifecycle runtime (startup, restart, readiness, health monitoring). After readiness it warms the most recently used directories (`getWarmupDirectories` dep, sequential and best-effort) because OpenCode initializes each directory lazily on first request and that cost would otherwise be paid by the user's first interactive session open.
 - `packages/web/server/lib/opencode/env-runtime.js`: OpenCode CLI/binary resolution and shell environment runtime.
 - `packages/web/server/lib/opencode/env-config.js`: OpenCode-related environment variable parsing and validation (host/port/hostname).
 - `packages/web/server/lib/opencode/hmr-state-runtime.js`: HMR-persistent runtime state initialization, auth-state bootstrap, and HMR sync helpers.
@@ -29,6 +29,7 @@ This module provides OpenCode server integration utilities for the web server ru
 - `packages/web/server/lib/opencode/upgrade-capability.js`: authoritative upgrade ownership policy for the active OpenCode runtime. Bundled, external, and unresolved runtimes fail closed; only managed non-bundled runtimes delegate upgrades to OpenCode.
 - `packages/web/server/lib/opencode/tunnel-wiring-runtime.js`: tunnel service/routes composition runtime and active-port wiring for main server startup.
 - `packages/web/server/lib/opencode/startup-pipeline-runtime.js`: server startup tail orchestration runtime for terminal/proxy/static/start-listen flow.
+- `packages/web/server/lib/opencode/startup-performance.js`: opt-in startup phase diagnostics with fixed labels and numeric metadata allowlists.
 - `packages/web/server/lib/agent-tool/runtime.js`: managed OpenCode custom-tool materialization, environment injection, loopback authentication, and fixed CLI action dispatch.
 - `packages/web/server/lib/system-prompt/runtime.js`: opt-in managed OpenCode system-prompt optimizer materialization and plugin injection.
 - `packages/web/server/lib/opencode/server-utils-runtime.js`: shared server runtime utilities for OpenCode proxy wiring, OpenCode port/readiness helpers, and snapshot fetchers.
@@ -121,6 +122,10 @@ runtime. PATH and `OPENCODE_SERVER_PASSWORD` remain lifecycle-owned and cannot
 be replaced by injected values. External OpenCode processes receive no
 OpenChamber tool injection.
 
+Set `OPENCHAMBER_STARTUP_PERF=1` to emit bounded startup phase records for server listen, managed OpenCode preparation/readiness, and proxy readiness holds. Every OpenCode bootstrap emits one terminal `opencode.bootstrap.ready` or `opencode.bootstrap.error` event, including reused and external server paths. Records contain controlled phase/outcome/route labels and timing values only; they never contain request URLs, runtime keys, directories, session IDs, credentials, or content.
+
+macOS `say` voice enumeration starts concurrently with server composition. The server listener and managed OpenCode startup do not wait for it; `/api/tts/say/status` awaits the same authoritative capability promise when queried before enumeration completes.
+
 Transport-triggered health checks share the periodic monitor's failure accounting interval. Rapid WS reconnect callbacks therefore cannot exhaust the managed-process restart threshold using one cached unhealthy result; an exited managed process still restarts immediately.
 
 ## Public exports (env-runtime.js)