docs(skills): add run-session skill

Covers the per-turn procedure: bootstrap, intent, deciding to roll, the
CLI, appending a scene, and applying state, with a session template.

.agents/skills/run-session/SKILL.md

@@ -0,0 +1,133 @@
+---
+name: run-session
+description: Run a turn or a full session of a solo journaling campaign. Use when the player describes what their character does, asks to start or continue a session, or asks what happens next. Interprets the message as in-fiction intent, rolls through the journal CLI, narrates the outcome in chat, appends it to the session log, and updates the PC sheet, clocks, threads, and world files.
+---
+
+# Running a session
+
+The player types their intent into chat, exactly as they would request a code
+change. Everything else is your job: resolve it with dice, narrate, and persist
+the result to the campaign's files. `AGENTS.md` holds the contract; this skill
+is the procedure for a single turn.
+
+The player never edits files. If you narrated it, write it down.
+
+## 1. Bootstrap the session
+
+Do this once, before the first turn.
+
+1. **Identify the campaign.** `journal games` lists games; the campaign is
+   `campaigns/<name>/`. If the player named one, use it. If several exist and
+   they did not, ask — do not guess. Only `campaigns/` directories without a
+   leading `_` count.
+2. **Read the campaign's game** from `campaigns/<name>/campaign.md` frontmatter
+   (`game: <id>`). Read `games/<id>/game.md` — it is authoritative — plus
+   `campaigns/<name>/house-rules.md`.
+3. **Load state.** Read the PC sheet(s) in `characters/`, `state/clocks.md`,
+   `state/threads.md`, and the tail of the newest `sessions/NNNN-*.md`.
+4. **No PC yet?** Build one from the game's `characters/` options (roll them
+   with `journal <command>` where the game provides one), write the sheet to
+   `campaigns/<name>/characters/<pc>.md`, and say what you created.
+5. **Pick the session file.** Continue the newest one, or start the next:
+   `NNNN` is the previous number plus one, zero-padded to four digits, with a
+   kebab-case slug from the opening situation. Use `templates/session.md`.
+
+## 2. Read the player's message
+
+- **In-fiction intent** — the player describing what the PC does, tries, or
+  asks. This is the main case: go to step 3. Record their words *verbatim* in
+  the `Player` block.
+- **Meta request** — a rules question, a recap, "what are my stats?", "start a
+  session". Answer from the files. Do not roll, do not append a scene, and do
+  not treat it as intent.
+
+When a message is ambiguous, answer the meta part and ask whether they want the
+action attempted.
+
+## 3. Decide whether to roll
+
+Roll only when the outcome is genuinely uncertain *and* both results would be
+interesting. Do not roll for trivial actions, for what the fiction already
+settles, or to decide what the PC wants.
+
+- **Oracle** — a yes/no question about the world: "Is the gate locked?" Ask one
+  question at a time, phrased so either answer is interesting.
+- **Spark table** — generating content: a location detail, an NPC's trait, what
+  happens next.
+- **Complication** — on `and`/`but` results, or when the fiction needs a twist.
+- **The game's own resolution** — if `game.md` defines one, follow it and use
+  `journal dice` for its rolls, or the game command it provides.
+
+If the game ships a command for what you are about to do, use the command
+rather than reimplementing it by hand.
+
+## 4. Roll
+
+Always pass `--campaign <name>`. Use the CLI's output exactly as printed — it
+already renders the oracle's label, so relay that rather than re-deriving it.
+
+```sh
+journal oracle "Is the gate locked?" --complicate --campaign ashfall
+journal roll sparks --campaign ashfall
+journal dice 2d6+1
+journal <game-command> --campaign ashfall
+```
+
+Never invent, reroll, or adjust a result. If a roll is not interesting, the
+mistake was calling for one — narrate from the fiction instead.
+
+## 5. Narrate and append
+
+Resolve the intent into a concrete outcome, then append one scene to the
+current session log using the format in `AGENTS.md`. Copy
+`templates/session.md` for a new file.
+
+- If you rolled, put the CLI output in backticks, verbatim.
+- Omit the roll line when no roll was needed.
+- List every mechanical change on the `State` line.
+- **Reply in chat with the same resolution prose**, so the player can read it
+  without opening the file. Keep chat and file consistent.
+
+## 6. Apply state changes
+
+The scene is not finished until the files match the `State` line.
+
+| Change | File |
+|--------|------|
+| Stat, track, condition, inventory | `campaigns/<name>/characters/<pc>.md` frontmatter |
+| A clock filled or advanced | `campaigns/<name>/state/clocks.md` |
+| A thread opened, resolved, abandoned | `campaigns/<name>/state/threads.md` |
+| A place, person, or faction first appears | new file under `world/` |
+| Something changes about an existing one | that file |
+| A rule shape that emerged in play | `campaigns/<name>/house-rules.md` |
+
+Never invent stats the game does not use. Keep the frontmatter shape the game
+defines.
+
+## Continuity rules
+
+- **Append only.** Never edit a past scene except to fix a typo the player
+  points out.
+- **Do not decide what the PC wants.** The oracle answers the world; the player
+  answers the character.
+- **Never copy game content into a campaign.** Reference the game package.
+- **Keep frontmatter and prose consistent.** If the log says a stat changed,
+  the sheet must show it.
+
+## Closing a session
+
+When the player stops for the night:
+
+1. Run `journal check --campaign <name>` and fix anything it reports.
+2. Make sure every `State` line has been applied.
+3. Leave `state/threads.md` reflecting what is unresolved.
+
+## Common failures
+
+- Inventing a dice result, or rolling without calling the CLI.
+- Rolling when the fiction already answers the question.
+- Paraphrasing the player in the `Player` block instead of quoting them.
+- Writing a `State` line but not applying it to the files.
+- Editing an earlier scene to "fix" continuity instead of writing the fix
+  forward.
+- Acting on the wrong campaign when several exist — ask first.