…t self-report

The recurring "display name ≠ actual name" bug: a Claude session's statusline
shows one wire identity while the session operates on wire as another. Confirmed
live — a dot session's statusline read daydream-gorge (its CLAUDE_CODE_SESSION_ID)
while its MCP served merry-spindle, a key matching no live session. Box-wide it's
systemic: 434 running wire procs, 115 serving an identity no live session uses.

Root cause: the long-lived `wire mcp` server resolves + FREEZES its identity at
launch; the statusline re-resolves live each render. When they diverge — the MCP
booted before Claude wrote its session pidfile, so resolve_session_key() missed
and the server minted a throwaway `mcp-proc-*` key, pinned it into WIRE_SESSION_ID,
and served it for life — you get two permanent names. The prior dash detection
(9c3b62a) couldn't see it: a fresh CLI's env is already live, so its env-vs-pidfile
check never inspected the frozen MCP process.

Fixes:
- session.rs: before minting at MCP startup, RETRY the pidfile (walk the ancestor
  chain ONCE, re-read only the cached pids across a short backoff — no per-hop `ps`
  re-fork, avoiding the #353 Windows perf trap). Recovers the live identity instead
  of freezing a throwaway one. Stop pinning the minted key into WIRE_SESSION_ID
  (that slot is the operator-override / live channel; a minted value parked there
  masqueraded as an override and beat the live session on re-resolve — the root of
  the split). WIRE_HOME already pins the process + is inherited by children.
- session.rs: redesign detect_identity_split to compare OPERATIONAL identity (the
  home this process serves) vs LIVE pidfile identity — so the frozen MCP itself
  detects the split, which the old env-vs-pidfile check structurally could not.
  Fixes a latent bug exposed by the redesign: handle_for_key sanitized the key
  before hashing, but homes are created from the raw key hash; sanitize_name
  truncates at 32 chars, so a 36-char session-id uuid resolved to the wrong home
  and the split silently returned None. (Caught by the in-situ gate, not units.)
- mcp.rs: surface `identity_split` in wire_status + wire_whoami (null when healthy)
  so an agent self-detects drift at the session-start health check it already runs,
  instead of waiting for a human to run `wire dash`.
- setup.rs: bake `env:{WIRE_SESSION_ID:"${CLAUDE_CODE_SESSION_ID}"}` into the
  canonical MCP entry `wire setup` writes, so the forward survives `--apply`
  (was a hand-edit the next apply overwrote). Inert on non-Claude hosts (the ${...}
  guard rejects an unexpanded value). Prevention for every new session.

Existing frozen MCPs heal on next /mcp reconnect; the fix + self-report make that
one-command recovery visible. 8 new tests; 643 lib tests green; fmt + clippy clean.
In-situ: reproduced the split with real homes/pidfile — banner fires; silent when
healthy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VxnZEjrcrYR3SAq8Crv8hg