feat(agentic-kit): run log + pi extension kernel — six additive packages (roll-up of #1723–#1728)

[pyramation]

Summary

Single merge point for the six additive packages from #1723–#1728 (kept open for per-package review; this branch is exactly their six commits). Together they are the M0 kernel from the greenfield design: one pi agent loop, an append-only run log as the source of truth, and placement expressed as configuration.

agentic/run-log                 record types, projectors, store contracts, memory + file stores
agentic/pi-ext-run-log          mirrors pi session entries into the log, verbatim
agentic/pi-ext-metered-model    routes model calls through agentic-server (authoritative metering)
agentic/pi-ext-usage-report     self-reports usage to the gateway's /v1/usage (own-key lane)
agentic/pi-ext-gate             tool-call policy + remote approvals over a DB/API rendezvous
agentic/pi-embed                composes the above into one session

const embedded = await startRun({
  runId, pi, cwd: workspace,
  log: { store },                                                // transcript + resume are projections of this
  metering: { mode: 'gateway', gatewayUrl, identity, models },    // or { mode: 'self-report', … } locally
  gate: { policy, approvals },
  extensions: [createDbTools(host)]
});

Load-bearing properties, in one place:

• pi entries are stored verbatim under a 4-field wrapper (runId, seq, recordedAt, piSessionVersion) — no re-encoding, so pi's own versioned session migrations keep working and a resumed session is a replay, not a translation.
• Appends are idempotent by (runId, seq) and the mirror only advances its cursor after a successful append, retrying the whole batch — so a crashed or resumed run cannot lose or duplicate entries.
• The two metering lanes are mutually exclusive by type. gateway is authoritative (the gateway meters what it proxies); self-report is the own-provider-key lane, documented as reconciliation/visibility rather than tamper-proof billing. Enabling both would double-count.
• The gate defaults to ask, not to trust — an undeclared tool is not implicitly permitted — and an approval timeout denies.
• No new transport. The stores are two interfaces (append, read by cursor); the wire stays the existing GraphQL API with agent_event rows as the rendezvous and the cursor read as the poll. No socket, no second envelope loop, no server.
• Nothing reads process.env and nothing reads a file it was not handed. Endpoints, tokens, identity, model list, policy and stores are all required options, so configuration stays hoisted to the host (@agentic-kit/pi's resolved context locally, injected CONSTRUCTIVE_* vars in a job).

Additive: six new directories, plus the CI package matrix line and the lockfile importers. No existing package, function or UI changes; desktop is untouched. Every package carries README + logo, makage build, and its own jest suite (164 tests across the six); all of #1723–#1728 are green.

Link to Devin session: https://app.devin.ai/sessions/450ce6d6659c47759c184ae6ec19a2a8
Requested by: @pyramation

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