feat(coding-agent): added builtin default rules and disable controls

- Added 14 bundled TTSR rules (TypeScript and Rust conventions) embedded into the binary via the lowest-priority `builtin-defaults` provider.
- Extracted rule bucketing into `bucketRules` with support for `disabledRules` and `builtinRules` settings.
- Added `ttsr.builtinRules` and `ttsr.disabledRules` settings to control which rules are active per session.

packages/coding-agent/src/capability/rule-buckets.ts

@@ -0,0 +1,64 @@
+/**
+ * Rule bucketing
+ *
+ * Single funnel that every discovered rule passes through on its way into a
+ * session. It applies the user's disable levers, registers TTSR rules with the
+ * manager, and splits the rest into the always-apply and rulebook buckets.
+ *
+ * Bucket precedence (matches docs/rulebook-matching-pipeline.md §5):
+ *   1. TTSR     — non-empty `condition` that `TtsrManager.addRule` accepts
+ *   2. always   — `alwaysApply === true`
+ *   3. rulebook — has a `description`
+ */
+import type { TtsrManager } from "../export/ttsr";
+import { BUILTIN_DEFAULTS_PROVIDER_ID, type Rule } from "./rule";
+
+export interface RuleBuckets {
+	rulebookRules: Rule[];
+	alwaysApplyRules: Rule[];
+}
+
+export interface BucketRulesOptions {
+	/** Rule names to drop entirely (bundled defaults and user rules alike). */
+	disabledRules?: readonly string[];
+	/** When false, drop every rule from the bundled `builtin-defaults` provider. */
+	builtinRules?: boolean;
+}
+
+/**
+ * Filter and bucket rules, registering TTSR rules on `ttsrManager` as a side
+ * effect. Disabled rules are dropped before any bucket assignment, so a
+ * disabled rule is neither matched as TTSR nor surfaced via `rule://`.
+ */
+export function bucketRules(
+	rules: readonly Rule[],
+	ttsrManager: TtsrManager,
+	options: BucketRulesOptions = {},
+): RuleBuckets {
+	const includeBuiltin = options.builtinRules !== false;
+	const disabled = new Set<string>();
+	for (const raw of options.disabledRules ?? []) {
+		const name = raw.trim();
+		if (name.length > 0) disabled.add(name);
+	}
+
+	const rulebookRules: Rule[] = [];
+	const alwaysApplyRules: Rule[] = [];
+
+	for (const rule of rules) {
+		if (disabled.has(rule.name)) continue;
+		if (!includeBuiltin && rule._source?.provider === BUILTIN_DEFAULTS_PROVIDER_ID) continue;
+
+		const isTtsrRule = rule.condition && rule.condition.length > 0 ? ttsrManager.addRule(rule) : false;
+		if (isTtsrRule) continue;
+		if (rule.alwaysApply === true) {
+			alwaysApplyRules.push(rule);
+			continue;
+		}
+		if (rule.description) {
+			rulebookRules.push(rule);
+		}
+	}
+
+	return { rulebookRules, alwaysApplyRules };
+}

packages/coding-agent/src/capability/rule.ts

@@ -9,6 +9,14 @@ import type { SourceMeta } from "./types";
 
 const CONDITION_GLOB_SCOPE_TOOLS = ["edit", "write"] as const;
 
+/**
+ * Provider id for the bundled default rules shipped with the agent.
+ * Lowest priority, so any user/project/tool rule of the same name overrides
+ * a bundled default. Also used to gate the whole bundled set via
+ * `ttsr.builtinRules`.
+ */
+export const BUILTIN_DEFAULTS_PROVIDER_ID = "builtin-defaults";
+
 /**
  * Parsed frontmatter from rule files.
  */