chore(v0.6): checkpoint foundation — Amber theme, P1 types, P3 config, design docs

Prior-session prep for the v0.6 Project Manager, checkpointed on the
v0.6-projects branch as a clean base for the parallel builders:

- P1 (src/types.ts): ProjectInfo + ProjectSessionRef contracts; Config
  gains projectRoots/projectScanDepth/projectScanTtlMs/projectDirtyCheck.
- P3 (src/config.ts): parseBool + parseProjectRoots helpers; parse the
  4 PROJECT_* env vars with defaults ([homeDir]/4/10000/true).
- UI: public/style.css indigo -> Amber (#e3a64a) accent theme.
- Docs: FEATURE_PROJECT_MANAGER.md (1:N session design), THEME.md,
  docs/mockups/ (final-amber.png is the locked visual).

Typecheck (backend + web) green. No behavior change to runtime code yet;
P2/P4/P5/P6 implement the feature on top of this.

src/types.ts

@@ -34,6 +34,11 @@ export interface Config {
   readonly previewBytes: number; // manage-page preview: bytes of scrollback tail rendered
   readonly useTmux: boolean; // H1: spawn the shell inside tmux so it survives a server restart
   readonly allowedOrigins: readonly string[]; // derived from NIC IPs, NOT bindHost (M1)
+  // v0.6 Project Manager — project discovery (impl: src/config.ts T-PM3)
+  readonly projectRoots: readonly string[]; // PROJECT_ROOTS, default [homeDir]
+  readonly projectScanDepth: number; // PROJECT_SCAN_DEPTH, default 4
+  readonly projectScanTtlMs: number; // PROJECT_SCAN_TTL, default 10000 (discovery cache)
+  readonly projectDirtyCheck: boolean; // PROJECT_DIRTY_CHECK, default true (git status per repo)
 }
 
 /** process.env is structurally assignable to this; keeps the file free of `NodeJS.*`. */
@@ -192,6 +197,31 @@ export interface LiveSessionInfo {
   rows: number;
 }
 
+/* ───────────────── project manager (v0.6, §4.3 FEATURE doc) ──────────────── */
+
+/** One running session belonging to a project (live-sessions归并 by cwd).
+ *  Mirrors LiveSessionInfo fields so buildProjects can map directly. */
+export interface ProjectSessionRef {
+  id: string;
+  title?: string; // tab title / derived label (e.g. 'claude', 'shell'); optional
+  status: ClaudeStatus; // reuse hook status (working|waiting|idle|unknown)
+  clientCount: number; // mirror devices currently attached
+  createdAt: number;
+  exited: boolean;
+}
+
+/** A discovered project (git repo or recently-used cwd) for the Projects panel.
+ *  impl: src/http/projects.ts buildProjects(cfg, liveSessions) — T-PM2. */
+export interface ProjectInfo {
+  name: string; // repo directory name
+  path: string; // absolute path
+  isGit: boolean;
+  branch?: string; // current branch (git repos only)
+  dirty?: boolean; // uncommitted changes (when projectDirtyCheck)
+  lastActiveMs?: number; // newest ~/.claude/projects mtime for this cwd; sort key
+  sessions: ProjectSessionRef[]; // running sessions in this project (1:N; may be empty)
+}
+
 export interface SessionManager {
   handleAttach(
     ws: WebSocketLike,