Include shared/ dir in repo (gitignore allowlist)

The previous commit referenced shared/ansi.ts, shared/format.ts, and
shared/ctx.ts but those files were filtered by the default-deny
.gitignore. Adding !/shared/ to the allowlist so the imports actually
resolve in a fresh clone.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -18,5 +18,6 @@
 !/mechanicus-status-line.ts
 !/mechanicus-thinking-label.ts
 !/scripts/
+!/shared/
 !/tests/
 !/themes/

shared/ansi.ts

@@ -0,0 +1,47 @@
+/**
+ * ANSI escape-sequence helpers shared across extensions.
+ *
+ * Kept free of relative imports so Node's --experimental-strip-types can load
+ * this directly in tests.
+ */
+
+export const ANSI_RESET_FG = "\x1b[39m";
+export const ANSI_RESET_ALL = "\x1b[0m";
+
+/**
+ * Convert `#rrggbb` (or `#rgb`) to [r, g, b] bytes. Throws on malformed input
+ * rather than silently producing NaN — previously the callers built broken
+ * ANSI codes out of `\x1b[38;2;NaN;NaN;NaNm` which some terminals render as
+ * bright cyan, giving mysterious color bugs.
+ */
+export function hexToRgb(hex: string): [number, number, number] {
+	const m = hex.trim().replace(/^#/, "");
+	const expanded =
+		m.length === 3 ? m.split("").map((c) => c + c).join("") : m;
+	if (!/^[0-9a-fA-F]{6}$/.test(expanded)) {
+		throw new Error(`Invalid hex color: ${hex}`);
+	}
+	const n = parseInt(expanded, 16);
+	return [(n >> 16) & 0xff, (n >> 8) & 0xff, n & 0xff];
+}
+
+/** Build a 24-bit foreground ANSI escape for an `#rrggbb` hex color. */
+export function fgFromHex(hex: string): string {
+	const [r, g, b] = hexToRgb(hex);
+	return `\x1b[38;2;${r};${g};${b}m`;
+}
+
+/**
+ * Strip every ANSI CSI escape sequence from a string. Useful when the
+ * renderer needs to know the visible width of a line that contains color
+ * codes.
+ */
+export function stripAnsi(s: string): string {
+	// biome-ignore lint/suspicious/noControlCharactersInRegex: CSI stripping is the point
+	return s.replace(/\x1b\[[0-9;]*[a-zA-Z]/g, "");
+}
+
+/** Count visible grapheme-less characters. Mirrors pi-tui's visibleWidth. */
+export function visibleWidth(s: string): number {
+	return stripAnsi(s).length;
+}

shared/ctx.ts

@@ -0,0 +1,43 @@
+/**
+ * Helpers for dealing with pi's ExtensionContext in the face of its
+ * "stale after session replacement or reload" semantics.
+ *
+ * Pi's ExtensionRunner throws when any captured ctx field is accessed after
+ * the runner has been torn down (on /quit, /reload, new session). This
+ * module provides a single guarded wrapper so every extension doesn't have
+ * to re-implement try/catch + null-on-shutdown patterns.
+ */
+
+/**
+ * Run `fn` with the given ctx, swallowing any "stale context" errors that
+ * occur when pi's runner has gone away between the event that captured ctx
+ * and the time we're now using it (TUI render timers, setInterval ticks,
+ * etc.). Returns `undefined` on failure.
+ */
+export function safely<T>(fn: () => T): T | undefined {
+	try {
+		return fn();
+	} catch {
+		return undefined;
+	}
+}
+
+/**
+ * Async variant of `safely`.
+ */
+export async function safelyAsync<T>(fn: () => Promise<T>): Promise<T | undefined> {
+	try {
+		return await fn();
+	} catch {
+		return undefined;
+	}
+}
+
+/** Minimal shape we rely on — avoids coupling every caller to ExtensionContext. */
+export interface UiLike {
+	hasUI: boolean;
+}
+
+export function hasUI(ctx: UiLike | null | undefined): ctx is UiLike & { hasUI: true } {
+	return !!ctx && ctx.hasUI === true;
+}

shared/format.ts

@@ -0,0 +1,29 @@
+/**
+ * Small formatting helpers. Pure, no side effects, no external imports.
+ */
+
+/**
+ * Format a token count as a compact human-readable string.
+ *   formatTokens(42)    = "42"
+ *   formatTokens(1234)  = "1.2k"
+ *   formatTokens(12345) = "12k"
+ */
+export function formatTokens(n: number): string {
+	if (n < 1000) return String(n);
+	if (n < 10_000) return `${(n / 1000).toFixed(1)}k`;
+	return `${Math.round(n / 1000)}k`;
+}
+
+/**
+ * Format a millisecond duration for the working indicator / timers.
+ *   formatElapsed(450)    = "0s"
+ *   formatElapsed(42_000) = "42s"
+ *   formatElapsed(90_500) = "1m 30s"
+ */
+export function formatElapsed(ms: number): string {
+	const total = Math.max(0, Math.floor(ms / 1000));
+	const m = Math.floor(total / 60);
+	const s = total % 60;
+	if (m > 0) return `${m}m ${s}s`;
+	return `${s}s`;
+}