Replace the footer's placeholder usage with a real observation ledger

The footer showed invented percentages. It now shows what two harnesses
actually report, or says it does not know.

lumbridge-core gains an append-only per-profile UsageLedger and a projection
that labels every derived value estimated, withholds a burn rate from a single
sample, withholds a window fraction with no reported ceiling, withholds an
exhaustion estimate that lands after the reset, and reports an expired window
as rolled over rather than freezing its last percentage. A missing fact renders
as missing, never as zero. (0012)

lumbridge-harness is the impure side: processes, clocks, and untrusted wire
text in, observations out. Three adapters:

- Codex's account/rateLimits/read over the app-server's JSON-RPC stdio. The
  client cannot express a request outside a two-variant enum and answers every
  server-to-client request with -32601, so a harness asking Lumbridge for a
  credential is refused by construction. (0013)
- Claude Code's session transcripts, as a byte-offset tail follower that
  reports nothing until the backlog is read to EOF — a partially-read backlog
  is indistinguishable from a burst of spend, and the first run against 20 MB
  reported forty-six billion tokens an hour. The parser models four counters,
  so the conversations in those files are not representable. (0014)
- Claude Code's five-hour and seven-day subscription windows, via a bridge
  installed as its statusLine command. 0014 had claimed no such surface
  existed; it does, and the record is corrected in place rather than quietly
  edited. Lumbridge does not read the OAuth credential to call the account
  usage endpoint, which is what comparable tools do — AGENTS.md forbids it,
  and 0015 says so rather than leaving the gap unexplained.

Also in here: a capability-check ordering fix in the workspace reducer, where
the applied-request replay table was consulted before the capability check and
so answered questions the caller had no right to ask; the GPUI spike wired to
the live probes with per-harness gauges and provenance chips; and a launcher
that matches its own window by PID, because GPUI sets WM_NAME but not
_NET_WM_NAME and a title match never succeeded.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/UI_SPIKE_SCORECARD.md

@@ -97,7 +97,13 @@ Terminal, Browser, Markdown, and Review panels beside the selection or
 reattaches an existing session. Every Terminal panel receives an independent
 actor-owned VT session; the three seed non-terminal surfaces keep deterministic
 updates running. Counters
-separate external PTY batches/lines from total model updates. The GPUI footer
+separate external PTY batches/lines from total model updates. The GPUI footer's
+usage zone is no longer a constant string: it renders a `lumbridge-core`
+projection for the selected panel's account profile, with a provenance chip and
+explicit unavailable phrases, and its sidebar attention count and runtime rows
+are derived from live panel and ledger state. The Floem shell still renders the
+static footer fixtures, so the two candidates are no longer comparable on that
+strip. The GPUI footer also
 reports dispatch-to-element-build p50/p95 over a bounded 256-sample window. It
 is deliberately not called key-to-present or frame-present latency: neither
 candidate exposes a reliable public cross-platform post-present callback. True