Record production tree v2 decisions and resource deposit rules

progression_design.md: rewrite the resource phases around the four
decided inputs (two mined everywhere, one deposit-gated mid resource,
one scrap-only late input), add the Resource deposits rule set
(freedom first / geography later, deposits only in expansions, patch
area as throughput cap, deterministic content, binary mining), note
the dual gating of the mid resource, and add the deposit-layer action
item.

content_design.md: mark the first-pass tree as superseded and record
the v2 decisions — iron/copper/quartz/voidsteel with their fiction
(M-type asteroid, quartz geodes, battle-forged voidsteel), titanium
dropped with its gating role moved to electronics and possibly a
quality-steel step, the material palette fingerprints, and the
laser-to-railgun rename with lasers reserved as a future weapon type.
Update the balancing target phase boundaries accordingly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DyCu8vwChKMbLJQ3xosYEN

docs/content_design.md

@@ -129,7 +129,12 @@ Maximum simultaneous (disjoint) placements: m guns — cruiser 2,
 battlecruiser 3, battleship 4; l guns — battleship 1, dreadnought 3;
 drone hangar — carrier 1.
 
-## Production tree
+## Production tree (first pass — superseded)
+
+**Superseded (July 2026):** this first-pass tree predates the rules in
+`docs/progression_design.md` and will be replaced. The decisions for the
+redesign are recorded in "Production tree v2 — decisions" below; the text
+of this section is kept for reference until the new tree lands.
 
 Design principle: each game phase adds exactly one new base input chain, so
 factory complexity ramps alongside ship size.
@@ -171,6 +176,59 @@ It verifies every consumed item has a producer, every item has a visuals
 entry, flags orphaned items, and prints which items are reprocessing-only
 (currently exactly advanced_alloy).
 
+## Production tree v2 — decisions (July 2026)
+
+The old tree is discarded; the new one is designed against the rules in
+`docs/progression_design.md` (ratio curve, cost ladder, cost archetypes,
+refactorability). Decisions fixed so far:
+
+### Base inputs (4) and fiction
+
+- **iron_ore, copper_ore** — from the start, minable on every asteroid
+  tile. Fiction: the asteroid is an M-type (metal) body — its bulk rock
+  *is* ore, which is why the shipyard operation was built here at all.
+- **quartz** — mid-game, minable only on geode deposit patches in
+  expansion territory (see the Resource deposits rules in
+  `progression_design.md`). Fiction: ordinary silicate dust is everywhere
+  and worthless; chips and optics need rare, pocket-bound optical-grade
+  crystal.
+- **voidsteel** — late-game, obtained only by reprocessing scrap.
+  Fiction: battle-forged — formed when weapon plasma anneals hull metal
+  in the violence of ship destruction. Any wreck yields it, including the
+  player's own; no foundry can replicate it.
+- **titanium is dropped.** Its hull-gating role moves to quartz-era
+  control systems ("you can smelt all the steel you want, but you cannot
+  steer a battlecruiser without electronics") and possibly a *quality*
+  steel step — e.g. a long-running hardened-steel recipe (time-heavy
+  archetype). Open question for the tree draft: quality step vs.
+  electronics-only gating; explicitly **not** sheer steel quantity alone.
+
+### Material palette (fingerprints per family)
+
+- **iron/steel** — structure.
+- **copper** — conduction and heat: wiring, coils, heat sinks.
+- **silicon family** (all derived from quartz): silicon (logic,
+  sensors), glass/optics (lenses, focusing crystals), ceramics (heat
+  shielding, insulators). Carries the non-metal variety without extra
+  base inputs.
+- **voidsteel** — capital-tier structure and exotics.
+- Deliberately skipped: carbon (mostly redundant with copper/ceramics),
+  plastics (drags in Factorio-style chemical chains; ceramics read more
+  sci-fi anyway), volatiles/ice (materials are build costs only — no
+  consumption mechanic to justify fuel).
+
+### Weapons
+
+- All current lasers are renamed to **railguns** (`laser_cannon_s/m/l` →
+  `railgun_s/m/l`); footprints and the gating matrix are unchanged.
+  Implementation stays as-is (instant damage application, no projectile,
+  no ammunition) — the beam visual reads as a tracer round. Materials:
+  iron slugs, copper coils, steel rails — the starting-metal fingerprint.
+- **Lasers are reserved for later** as a genuinely distinct weapon type
+  (e.g. once projectile/ammunition mechanics exist for other families),
+  arriving with quartz optics. More weapon types are planned; railguns
+  are simply the baseline tech that ships with v1.
+
 ## Balancing targets (first pass, July 2026)
 
 The six root numbers for the balancing pass. Every derived value (threat
@@ -189,8 +247,8 @@ targets deliberately ignore that; playtesting will show real run lengths.
 1. **Run length** — a winning run takes up to 2 hours of game time: win
    around boss cycle 20–24. Losing runs end earlier.
 2. **Phase boundaries** — early = cycles 1–5 (iron/copper, small hulls),
-   mid = cycles 6–14 (titanium, medium hulls), late = cycles 15+
-   (advanced alloy, capitals). Push cadence roughly one station set per
+   mid = cycles 6–14 (quartz, medium hulls), late = cycles 15+
+   (voidsteel, capitals). Push cadence roughly one station set per
    cycle from mid onward. This fixes the `unlock_at_station_level`
    ladder and, with the artifact win count, the `artifact_chance_formula`
    pacing.