test: Tier 1 static validation — 34 tests for SKILL.md command correctness

- test/helpers/skill-parser.ts: extracts $B commands from code blocks, validates against registry
- test/skill-parser.test.ts: 13 parser/validator unit tests
- test/skill-validation.test.ts: 13 tests validating all SKILL.md files + registry consistency
- test/gen-skill-docs.test.ts: 8 generator tests (categories, sorting, freshness)

test/helpers/skill-parser.ts

@@ -0,0 +1,133 @@
+/**
+ * SKILL.md parser and validator.
+ *
+ * Extracts $B commands from code blocks, validates them against
+ * the command registry and snapshot flags.
+ *
+ * Used by:
+ *   - test/skill-validation.test.ts (Tier 1 static tests)
+ *   - scripts/skill-check.ts (health summary)
+ *   - scripts/dev-skill.ts (watch mode)
+ */
+
+import { ALL_COMMANDS } from '../../browse/src/commands';
+import { parseSnapshotArgs } from '../../browse/src/snapshot';
+import * as fs from 'fs';
+
+export interface BrowseCommand {
+  command: string;
+  args: string[];
+  line: number;
+  raw: string;
+}
+
+export interface ValidationResult {
+  valid: BrowseCommand[];
+  invalid: BrowseCommand[];
+  snapshotFlagErrors: Array<{ command: BrowseCommand; error: string }>;
+  warnings: string[];
+}
+
+/**
+ * Extract all $B invocations from bash code blocks in a SKILL.md file.
+ */
+export function extractBrowseCommands(skillPath: string): BrowseCommand[] {
+  const content = fs.readFileSync(skillPath, 'utf-8');
+  const lines = content.split('\n');
+  const commands: BrowseCommand[] = [];
+
+  let inBashBlock = false;
+
+  for (let i = 0; i < lines.length; i++) {
+    const line = lines[i];
+
+    // Detect code block boundaries
+    if (line.trimStart().startsWith('```')) {
+      if (inBashBlock) {
+        inBashBlock = false;
+      } else if (line.trimStart().startsWith('```bash')) {
+        inBashBlock = true;
+      }
+      // Non-bash code blocks (```json, ```, ```js, etc.) are skipped
+      continue;
+    }
+
+    if (!inBashBlock) continue;
+
+    // Match lines with $B command invocations
+    // Handle multiple $B commands on one line (e.g., "$B click @e3       $B fill @e4 "value"")
+    const matches = line.matchAll(/\$B\s+(\S+)(?:\s+([^\$]*))?/g);
+    for (const match of matches) {
+      const command = match[1];
+      let argsStr = (match[2] || '').trim();
+
+      // Strip inline comments (# ...) — but not inside quotes
+      // Simple approach: remove everything from first unquoted # onward
+      let inQuote = false;
+      for (let j = 0; j < argsStr.length; j++) {
+        if (argsStr[j] === '"') inQuote = !inQuote;
+        if (argsStr[j] === '#' && !inQuote) {
+          argsStr = argsStr.slice(0, j).trim();
+          break;
+        }
+      }
+
+      // Parse args — handle quoted strings
+      const args: string[] = [];
+      if (argsStr) {
+        const argMatches = argsStr.matchAll(/"([^"]*)"|(\S+)/g);
+        for (const am of argMatches) {
+          args.push(am[1] ?? am[2]);
+        }
+      }
+
+      commands.push({
+        command,
+        args,
+        line: i + 1, // 1-based
+        raw: match[0].trim(),
+      });
+    }
+  }
+
+  return commands;
+}
+
+/**
+ * Extract and validate all $B commands in a SKILL.md file.
+ */
+export function validateSkill(skillPath: string): ValidationResult {
+  const commands = extractBrowseCommands(skillPath);
+  const result: ValidationResult = {
+    valid: [],
+    invalid: [],
+    snapshotFlagErrors: [],
+    warnings: [],
+  };
+
+  if (commands.length === 0) {
+    result.warnings.push('no $B commands found');
+    return result;
+  }
+
+  for (const cmd of commands) {
+    if (!ALL_COMMANDS.has(cmd.command)) {
+      result.invalid.push(cmd);
+      continue;
+    }
+
+    // Validate snapshot flags
+    if (cmd.command === 'snapshot' && cmd.args.length > 0) {
+      try {
+        parseSnapshotArgs(cmd.args);
+      } catch (err: any) {
+        result.snapshotFlagErrors.push({ command: cmd, error: err.message });
+        continue;
+      }
+    }
+
+    result.valid.push(cmd);
+  }
+
+  return result;
+}