refactor(status): rename blocked → waiting and blocked_api → rate_limited

[proboscis]

Summary

Rename run statuses blocked → waiting and blocked_api → rate_limited across the entire orch codebase for clarity. "Blocked" was misleading for both users and LLM agents — it implies an error when the run is simply idle awaiting input.

Closes: orch-449

Changes

Core (Go)

• Proto: RUN_STATUS_WAITING = 4, RUN_STATUS_RATE_LIMITED = 5 (numeric IDs preserved)
• Constants: All StatusBlocked/StatusBlockedAPI identifiers renamed
• Compat shims: NormalizeStatus() and NormalizeRunStatus() map old names → new
• All raw model.Status(string) casts replaced with NormalizeStatus() (6+ sites)
• Config: ShouldNotify() and validSlackNotifyStatuses accept both old+new names
• CLI flags: --only-blocked → --only-waiting, display abbrevs "wait" / "rlimit"
• Proto conversion: stringToProtoRunStatus accepts both; protoRunStatusToString outputs new only

Python TUI

• Enums, mappings, config defaults, widget display functions all updated

VSCode Extension

• runsProvider.ts case statements + package.json enum schema

Tests

• Unit tests for NormalizeStatus and NormalizeRunStatus
• All existing test expectations updated
• GitHub backend test: added "status:waiting" label mapping
• Backward compat tested via old name inputs in slack, proto, config tests

Documentation

• ~25 markdown files updated across docs/, specs/, plugins/, README

Backward Compatibility

Layer	Strategy
Vault files	NormalizeStatus("blocked") → StatusWaiting — no migration needed
User configs	notify_on: [blocked] continues to work
GitHub labels	status:blocked still maps correctly
Proto wire format	Numeric IDs 4/5 unchanged
New events	Always write waiting / rate_limited

Verification

• go build ./... passes
• go test ./... passes (1 pre-existing failure in TestApplyConfigDefaultsFallbacks unrelated to this PR)
• make lint passes (semgrep architecture rules)
• Pre-commit hooks pass
• No stale StatusBlocked identifiers remain
• All "blocked" string literals are in compat shim code, config compat, or tests only
• Test vault fixture kept as | status | blocked to verify compat parsing