Add model_size experiment to 5 daily workflows; introduce small-agent alias

[Copilot]

Wires a 50/50 model_size A/B experiment into 5 eligible daily workflows (no existing experiments, no subagents) to measure whether small models match full-model quality at lower token cost. Adds the small-agent builtin alias to make the experiment variants resolve at runtime.

Model alias

• New small-agent alias: ["haiku", "gpt-5-mini", "gemini-flash", "any"] — parallel to agent but targeting small/fast models

Experiment

Added to daily-doc-updater, daily-function-namer, daily-doc-healer, daily-caveman-optimizer (claude), and daily-cache-strategy-analyzer (codex):

experiments:
  model_size:
    variants: [agent, small-agent]
    metric: effective_tokens_total
    secondary_metrics: [run_success_rate, run_duration_ms]
    guardrail_metrics:
      - name: run_success_rate
        threshold: ">=0.90"
      - name: empty_output_rate
        threshold: "<=0.10"
    min_samples: 20
    weight: [50, 50]
    start_date: "2026-06-04"

Each workflow's engine is expanded to pass the selected variant as the runtime model:

engine:
  id: claude
  model: "${{ needs.activation.outputs.model_size }}"

[Copilot]

Pull request overview

This PR introduces a new built-in model alias (small-agent) and wires a model_size A/B experiment into 5 daily workflow source files to compare small/fast models vs the default agent chain using token-cost and reliability metrics. It also updates several golden fixtures and many generated workflow lockfiles.

Changes:

• Add small-agent to the built-in model alias map and extend unit tests accordingly.
• Add a model_size experiment + dynamic engine.model selection to 5 daily workflow source markdown files.
• Update WASM golden fixtures and many *.lock.yml generated workflows (including new Copilot settings injection).

Show a summary per file

File	Description
pkg/workflow/data/model_aliases.json	Adds the small-agent built-in alias chain.
pkg/workflow/model_aliases_test.go	Extends built-in alias test coverage to include small-agent.
.github/workflows/daily-doc-updater.md	Adds model_size experiment + sets engine.model from activation output.
.github/workflows/daily-doc-healer.md	Adds model_size experiment + sets engine.model from activation output.
.github/workflows/daily-function-namer.md	Adds model_size experiment + sets engine.model from activation output.
.github/workflows/daily-caveman-optimizer.md	Adds model_size experiment + sets engine.model from activation output.
.github/workflows/daily-cache-strategy-analyzer.md	Adds model_size experiment + sets engine.model from activation output (codex engine).
pkg/workflow/testdata/TestWasmGolden_CompileFixtures/with-imports.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_CompileFixtures/smoke-copilot.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_CompileFixtures/playwright-cli-mode.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_CompileFixtures/basic-copilot.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_AllEngines/pi.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_AllEngines/gemini.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_AllEngines/copilot.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_AllEngines/codex.golden	Updates embedded AWF config golden output to include small-agent.
pkg/workflow/testdata/TestWasmGolden_AllEngines/claude.golden	Updates embedded AWF config golden output to include small-agent.
.github/workflows/daily-mcp-concurrency-analysis.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-malicious-code-scan.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-issues-report.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-hippo-learn.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-geo-optimizer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-firewall-report.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-file-diet.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-experiment-report.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-compiler-threat-spec-optimizer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-compiler-quality.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-community-attribution.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-cli-tools-tester.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-cli-performance.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-byok-ollama-test.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-assign-issue-to-user.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-architecture-diagram.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-ambient-context-optimizer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/daily-agent-of-the-day-blog-writer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/craft.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/copilot-pr-prompt-analysis.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/copilot-pr-nlp-analysis.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/copilot-pr-merged-report.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/copilot-opt.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/copilot-cli-deep-research.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/contribution-check.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/constraint-solving-potd.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/code-simplifier.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/code-scanning-fixer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/cli-consistency-checker.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/ci-coach.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/chaos-pr-bundle-fuzzer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/breaking-change-checker.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/brave.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/bot-detection.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/auto-triage-issues.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/artifacts-summary.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/architecture-guardian.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/archie.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/agent-persona-explorer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/agent-performance-analyzer.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/ace-editor.lock.yml	Injects Copilot settings file write + cleanup trap in run script.
.github/workflows/ab-testing-advisor.lock.yml	Injects Copilot settings file write + cleanup trap in run script.

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• Files reviewed: 58/58 changed files
• Comments generated: 3