COD-80 raise terminal history/scrollback/buffer defaults

Bump the centralized terminal-history defaults: tmux scrollback 50k->100k and
PTY buffer cap 2MB->32MB (trim 1.5MB->24MB). Both remain env/settings overridable
and bounds-clamped. Worst-case 20-session buffer budget rises 40MB->640MB.
Stacked on the terminal-history config commit.

src/config/buffer-limits.ts

@@ -6,10 +6,9 @@
  * it easy to tune memory usage.
  *
  * Memory Budget Rationale (for 20 concurrent sessions):
- * - Terminal buffer: 2MB max × 20 = 40MB worst case
+ * - Terminal buffer: 32MB max × 20 = 640MB worst case
  * - Text output: 1MB max × 20 = 20MB worst case
  * - Messages: ~1KB each × 1000 × 20 = 20MB worst case
- * - Total buffer overhead: ~80MB (acceptable for a long-running server)
  *
  * @module config/buffer-limits
  */

src/config/terminal-history.ts

@@ -1,19 +1,19 @@
 /**
  * Defaults, bounds, and resolution for terminal history retention.
  *
- * Centralizes the terminal scrollback, tmux history-limit, and server PTY buffer
- * byte caps that were previously scattered as hardcoded literals. Each value is
- * overridable (env var or the settings object) and clamped to a sane range via
- * resolveTerminalHistoryConfig(). Defaults intentionally match the prior
- * hardcoded values, so introducing this module is behavior-neutral.
+ * Defaults are sized to retain a full default scrollback for replay:
+ * - browser/tmux scrollback: 50,000 -> 100,000 lines
+ * - server PTY buffer cap: 2MB -> 32MB (room for 100k normal-width lines + ANSI)
+ * All values remain env- and settings-overridable and bounds-clamped via
+ * resolveTerminalHistoryConfig().
  */
 
-export const DEFAULT_TERMINAL_SCROLLBACK_LINES = 50_000;
-export const DEFAULT_TMUX_HISTORY_LIMIT = 50_000;
+export const DEFAULT_TERMINAL_SCROLLBACK_LINES = 100_000;
+export const DEFAULT_TMUX_HISTORY_LIMIT = 100_000;
 export const DEFAULT_TERMINAL_BUFFER_MAX_BYTES =
-  parseInt(process.env.CODEMAN_MAX_TERMINAL_BUFFER || '', 10) || 2 * 1024 * 1024;
+  parseInt(process.env.CODEMAN_MAX_TERMINAL_BUFFER || '', 10) || 32 * 1024 * 1024;
 export const DEFAULT_TERMINAL_BUFFER_TRIM_BYTES =
-  parseInt(process.env.CODEMAN_TRIM_TERMINAL_TO || '', 10) || 1.5 * 1024 * 1024;
+  parseInt(process.env.CODEMAN_TRIM_TERMINAL_TO || '', 10) || 24 * 1024 * 1024;
 
 export const MIN_TERMINAL_SCROLLBACK_LINES = 1_000;
 export const MAX_TERMINAL_SCROLLBACK_LINES = 1_000_000;

test/terminal-history.test.ts

@@ -22,11 +22,11 @@ describe('resolveTerminalHistoryConfig', () => {
     });
   });
 
-  it('defaults match the prior hardcoded values (behavior-neutral)', () => {
-    expect(DEFAULT_TMUX_HISTORY_LIMIT).toBe(50_000);
-    expect(DEFAULT_TERMINAL_SCROLLBACK_LINES).toBe(50_000);
-    expect(DEFAULT_TERMINAL_BUFFER_MAX_BYTES).toBe(2 * 1024 * 1024);
-    expect(DEFAULT_TERMINAL_BUFFER_TRIM_BYTES).toBe(1.5 * 1024 * 1024);
+  it('defaults raise tmux scrollback to 100k and terminal buffer cap to 32MB', () => {
+    expect(DEFAULT_TMUX_HISTORY_LIMIT).toBe(100_000);
+    expect(DEFAULT_TERMINAL_SCROLLBACK_LINES).toBe(100_000);
+    expect(DEFAULT_TERMINAL_BUFFER_MAX_BYTES).toBe(32 * 1024 * 1024);
+    expect(DEFAULT_TERMINAL_BUFFER_TRIM_BYTES).toBe(24 * 1024 * 1024);
   });
 
   it('passes valid in-range values through unchanged', () => {
@@ -80,9 +80,9 @@ describe('resolveTerminalHistoryConfig', () => {
   });
 
   it('caps the default trim to a lowered max', () => {
-    // Default trim (1.5MB) exceeds a 1MB max → trim must fall to the max.
-    const cfg = resolveTerminalHistoryConfig({ terminalBufferMaxBytes: 1 * 1024 * 1024 });
-    expect(cfg.terminalBufferTrimBytes).toBe(1 * 1024 * 1024);
+    // Default trim (24MB) exceeds a 2MB max → trim must fall to the max.
+    const cfg = resolveTerminalHistoryConfig({ terminalBufferMaxBytes: 2 * 1024 * 1024 });
+    expect(cfg.terminalBufferTrimBytes).toBe(2 * 1024 * 1024);
   });
 
   it('truncates fractional inputs to integers', () => {