Require Playwright E2E tests in every verification step

- New skill e2e-testing: on-demand Playwright setup (config, test:e2e script), acceptance-criteria-driven specs (one per feature + app-shell smoke), blueprint-driven semantic locators, and the shared verification checklist
- /add-feature Step 7 and /execute-milestones Step 2.6 now write/update E2E specs and run npm run test:e2e alongside test/lint/typecheck; milestone gates and completion criteria include E2E
- /generate-app Step 5 sets up Playwright and creates the app-shell smoke spec for the web target (integration_test / UI automation noted for flutter/winui3)
- steering tasklist template, milestone-planning Definition of Done, milestone-execution task slicing/gates, development-guidelines pointers, and implementation-validator checks updated
- CLAUDE.md, README, and settings.json updated

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.claude/commands/execute-milestones.md

@@ -103,15 +103,19 @@ Use the `Task` tool to launch the `implementation-validator` subagent:
 - `description`: "Milestone implementation validation"
 - `prompt`: "Please validate the quality of all changes implemented for milestone `[NN] [name]`. The target files are `[list of implemented file paths]`. Focus on coding standards, error handling, testability, consistency with existing patterns, and whether every feature's acceptance criteria in `.steering/[dir]/requirements.md` are met."
 
-#### 2.6 Run Automated Tests
+#### 2.6 Run Automated Tests (including Playwright E2E)
+
+1. Write or update the milestone's end-to-end tests following the **e2e-testing skill** (`Skill('e2e-testing')`): one `e2e/[feature-name].spec.ts` per feature in the milestone, covering its acceptance criteria. Set up Playwright first (as described in the skill) if it is missing.
+2. Run:
 
 ```bash
 Bash('npm test')
 Bash('npm run lint')
 Bash('npm run typecheck')
+Bash('npm run test:e2e')
 ```
 
-If any command fails, analyze, fix, and re-run until all pass.
+If any command fails, analyze, fix, and re-run until all pass. Never skip or delete a failing test to make verification pass.
 
 #### 2.7 Retrospective and Document Reconciliation
 
@@ -124,7 +128,7 @@ Apply `/add-feature` Step 8 for the milestone:
 
 #### 2.8 Milestone Gate — then Continue
 
-The milestone is done only when: all tasks are `[x]`, validation passed, tests/lint/typecheck are green, the six documents are reconciled, and the milestone status is updated in the phase file and the roadmap.
+The milestone is done only when: all tasks are `[x]`, validation passed, tests/lint/typecheck/E2E (Playwright) are green, the six documents are reconciled, and the milestone status is updated in the phase file and the roadmap.
 
 **Once the gate passes, never stop; immediately start Step 2 for the next milestone in the queue.** If the gate genuinely cannot be passed (external blocker), record the blocker in the milestone's `tasklist.md`, the phase file, and `roadmap.md`, then stop and report — this is the only permitted early stop.
 
@@ -138,7 +142,7 @@ The milestone is done only when: all tasks are `[x]`, validation passed, tests/l
 - Every milestone in the specified phase file has status `Completed`.
 - The phase's status is `Completed` in both the phase file and `docs/milestones/roadmap.md`.
 - Each executed milestone has its own `.steering/[date]-milestone-[NN]-[name]/` directory with all tasks `[x]`.
-- Tests, lint, and typecheck pass on the final state.
+- Tests, lint, typecheck, and Playwright E2E tests pass on the final state, with E2E coverage for every implemented feature's acceptance criteria.
 - The six persistent documents reflect everything implemented.
 
 Completion message: