Ship the 0.8.0 first-hour and campaign milestone

Add the campaign shell, pause-safe checkpoint resume, post-shift campaign
continue, confirmed campaign reset, difficulty presets, searchable Help,
content-matrix validation, recovery events, contextual dialogue, policy/debrief
context and eligible-event previews. Extend persistence with atomic separate
files and add campaign/checkpoint/tutorial smokes. Headless 247/247, Python
94/94, tutorial/campaign/session/scenario smokes green.

CHANGELOG.md

@@ -4,6 +4,33 @@ All notable user-facing changes to Gig Line. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and versions use
 Semantic Versioning.
 
+## [0.8.0] — 2026-11-01
+
+### Added
+
+- A first-shift tutorial with contextual prompts, a safe visitor and replay/skip.
+- A three-venue campaign shell with shift progression and a Continue action.
+- Resume-from-checkpoint for paused shifts, including NPC, incident and system state.
+- Easy/normal/hard difficulty presets for spawn pacing, compliance tolerance and
+  report strictness.
+- A searchable in-game Help overlay with controls and the current venue policy.
+- Recovery events, contextual NPC dialogue and an eligible-event debug preview.
+
+### Changed
+
+- The shift review now includes venue policy, campaign next steps and continued
+  review controls.
+- Event scheduling suppresses recently played scripted events and respects the
+  difficulty spawn multiplier.
+- Save data is written atomically and split into settings, campaign, shift
+  history and versioned checkpoint files.
+
+### Fixed
+
+- Missing/older settings migrate through defaults; a partial write cannot
+  replace a valid save.
+- The HUD debug overlay now refreshes and shows the next eligible events.
+
 ## [0.7.3] — 2026-11-01
 
 ### Fixed