test: broaden coverage of analysis, OTel merge, and rendering

Add offline edge-case tests derived from patterns observed in real local
Copilot sessions, using synthetic/anonymized/simplified payloads that keep the
real event structure but carry invented IDs and trimmed counts (no session is
copied verbatim):

- Stale prompt-cache compaction: cache_read=0 with the whole context re-billed
  as cache_write, carrying the non-default live Opus costPerBatch rates. The
  rates + token counts price out to exactly the source session's totalNanoAiu,
  so rate-reconciliation is exercised for real. Asserts rates_from_compaction
  reads the live (non-default) rates and the cold-cache AIU split differs from
  the default-rate split.
- Multiple compactions in one long session: n_compactions accumulation, peak
  context = max pre-compaction size, compaction_aiu summation.
- compaction_start + compaction_complete peak interplay.
- Transient API failures with no shutdown degrade gracefully: API timeout
  (ETIMEDOUT, "retried 5 times"), socket drop, and user abort are tallied in
  event_type_counts but never fabricate economics; per-message token counts are
  still recovered. A timeout earlier in a session does not suppress the final
  shutdown's authoritative totals.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

test: harden session analysis against real-world edge cases

Replace the awkward flat-then-suffixed Pier rerun scheme with a clean nested jobs/<job-name>/<run-id>/ layout that separates stable job identity from per-run timestamp ids. Expose copyable job-name/run-id selectors via list, and let show, inspect, and �nalyze resolve an exact run from a selector (legacy run id, Pier job, or job/run). Add actionable not-found hints pointing back at list.

Persist stable job identity in a per-run manifest, derive selectors for the index, and update docs, experiment-repo templates, and ADR-0019. Commit a didactic project-scoped canvas that visualizes the verified structure.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…b-structure

Remove the legacy native runner, dry-run command, SQLite index, and legacy result layout. Standardize storage, summaries, docs, templates, and the structure canvas around Pier jobs, agents, tasks, trials, and runs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Forward --name through the scaffold helper's project_name parameter and cover the CLI init path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Simplify CLI around Pier jobs