fix: telemetry/memory flag mismatches, doc drift; add CI; self-dogfood

Parallel fleet audit (2 background agents) + direct work:

- src/commands/memory.mjs: `memory put --allow-secrets` was read as
  `flags.allowSecrets` (camelCase) but the CLI parser only emits
  kebab-case keys, so the flag was always undefined/false. Fixed to
  `flags['allow-secrets']`.
- Docs: `lh graph --brief` was referenced 14x across 5 agent.md files,
  harness.instructions.md, 4 SKILL.md files, onboard.prompt.md, and
  README, but `lh graph` has no --brief flag (terse output is already
  the default, --json/--severity are the only flags). Corrected every
  reference to match actual CLI surface.
- .github/workflows/ci.yml: run npm install/validate/test on node 20+22.
- Self-dogfooded `lh init --yes` in this repo, producing .agents/
  (harness.config.json, architecture.md, conventions.md, memory
  shards). `lh doctor` now reports all required checks green.
- Deduped .gitignore harness block against init's auto-managed block.

Verified: 53/53 tests pass, validate 0 errors, doctor all-green.

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

.agents/architecture.md

@@ -0,0 +1,30 @@
+# agents-2026 architecture
+
+<!-- Living document. Update when components, data flow, invariants, or ADR outcomes change. Keep claims concrete and current. -->
+
+## Purpose
+
+Describe what this system exists to do, who uses it, and what success means.
+
+## System context
+
+List upstream callers, downstream services, data stores, queues, files, and trust boundaries.
+
+## Components
+
+- Component: responsibility, owner, key files.
+
+## Data flow
+
+1. Input source.
+2. Validation and transformation.
+3. Persistence or external calls.
+4. Output and observability.
+
+## Key invariants
+
+- Invariant: why it must hold, where enforced, how verified.
+
+## Decision log (ADRs)
+
+<!-- Append ADR links or summaries here. Newest last. -->