feat(ai): add Fireworks Fire Pass support + AI provider review fixes

Fire Pass support:
- New provider with login command 'omp /login firepass'
- Hand-seeded kimi-k2.6-turbo model with Fire Pass router wire id
- pi-ai CLI --help lists firepass

AI provider fixes surfaced during the Fire Pass review:
- service_tier whitelist restored for openai/openai-codex only (was leaking to
  Fireworks, Firepass, OpenRouter, Azure OpenAI Responses)
- Anthropic tool schema normalizer collapses {} -> true for additionalProperties
- anthropic.prepareParams fires onPayload after drop helpers so callers see the
  real wire body
- isServiceTier type guard narrowed to ResolvedServiceTier
- transformMessages stops dropping orphan tool_result when all pending tool
  calls have already resolved
- zodToWireSchema preserves null for non-scalar nullable() inner schemas
- isEmptyObject / isJsonObjectEmpty use Object.keys().length === 0 instead of
  prototype-walking for...in
- Telemetry records resolved service_tier (priority) instead of scoped
  placeholder (openai-only/claude-only)
- Robomp dirty-state reminder no longer asserts a formatter-failure premise

python/robomp/src/prompts/dirty_state_reminder.md

@@ -9,7 +9,7 @@ Workspace state at end of your turn:
 
 Either of these counts being non-zero means roboomp will discard your work when this session ends. Read the summary above and act on it:
 
-- **Uncommitted changes** → stage and commit them (or `git restore` if they were unintentional). Re-run `bun run fix` afterward — your last push refusal was a formatter failure, so the same gate will reject this push too if `fix` exits non-zero.
+- **Uncommitted changes** → stage and commit them (or `git restore` if they were unintentional). If the work is ready, run `bun run fix` before committing — formatter and lint gates reject pushes when `fix` exits non-zero.
 - **Unpushed commits** → call `gh_push_branch` once `bun run fix` succeeds. If the push still refuses for a different reason, fix that root cause; do not skip the gate.
 
 If your fix is genuinely complete and the gates pass, push and then comment back on the PR with a one-line summary of what changed since the previous push. Do not re-classify the issue, do not re-post the original preamble, and do not call `abort_task` — this is recoverable.