Wires the pty-session-lease primitive (3aada48b) into terminal-agent so
the Commit 2 work in server.ts (next commit) can route /pty-restart and
re-attach by session identity rather than by single-use token.
Changes:
* validTokens: Set<string> → Map<string, string|null>. Each grant carries
its bound sessionId (or null for legacy single-grant callers). On WS
upgrade, the agent surfaces the bound sessionId via ws.data so open()
can register the session in the new reverse index.
* sessionsById: Map<sessionId, PtySession> — populated in open(),
cleared in close(). Required so /internal/restart can find and dispose
one specific session by id rather than enumerating all live sessions.
* /internal/restart: scoped to one sessionId. Codex T2 of the eng review
caught the gap — pre-spec the route would have disposed every PTY on
the agent, breaking pair-agent and any future multi-sidebar setup.
The body now requires `{sessionId}`; missing or unknown id returns
`{killed: 0}` and leaves siblings alone.
* maybeSpawnPty(ws, session): hoisted from the inline binary-frame spawn
block so both the legacy "spawn on first keystroke" trigger AND the
new `{type:"start"}` text-frame trigger land in the same code path.
Idempotent on session.spawned.
* `{type:"start"}` text frame: explicit spawn trigger. forceRestart
(extension side, lands in Commit 2C) sends this immediately on every
fresh WS so claude boots without requiring a keystroke. Pre-v1.44 the
lazy-binary-spawn pattern made the restart feel stuck.
* close(ws): drops the sessionsById entry alongside the existing
sessions WeakMap + validTokens cleanup. Commit 3 will revisit this to
keep the session alive for a 60s detach window before disposing.
Test (browse/test/terminal-agent-session-routing.test.ts):
* 8 static-grep tripwires pinning the load-bearing properties: validTokens
is a Map (not Set), sessionsById exists, /internal/restart is scoped
(negative-assert against enumerate-all patterns), WS upgrade plumbs
sessionId, maybeSpawnPty is the single spawn entry, close() drops the
index. Live spawn cycles belong in the e2e tier.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
449144cda5