fix(input): Windows Shift/Ctrl were dead + injected keys made no edges

[proggeramlug]

Two input bugs, both of which silently disabled whole features rather than
failing loudly.

1. Shift/Ctrl/Alt never registered on Windows

map_keycode only knew the side-specific modifier codes (VK_LSHIFT 0xA0,
VK_LCONTROL 0xA2, …). But Windows delivers the generic VK in
WM_KEYDOWN/UP — VK_SHIFT (0x10) for either shift, VK_CONTROL (0x11) for
either ctrl. The side-specific codes come back only from GetKeyState, never in
the message wParam. So map_keycode(0x10) hit _ => 0 and the press was
dropped: every Shift and Ctrl vanished before reaching isKeyDown().

Consequence in the shooter: sprint (Shift) and dodge (Ctrl) silently never
fired on Windows. Only letters/arrows/F-keys ever worked — which is why WASD,
Space, R and Q were fine and nobody spotted it.

resolve_modifier_vk() recovers the side from lParam (scancode for shift —
LShift 0x2A / RShift 0x36; the extended-key bit for ctrl/alt) and runs before
map_keycode in both wndprocs (standalone + embedded subclass).

2. Injected keys never produced an isKeyPressed edge

keys_pressed is computed in begin_frame as keys_down && !prev_keys_down,
but prev_keys_down is copied in end_frame. A real key arrives in
poll_events() — before begin_frame — so it gets an edge. An injected
key is raised from the game loop, after begin_frame, so end_frame folded it
into prev_keys_down before begin_frame ever looked. isKeyDown() saw it;
isKeyPressed() never did — making the injection API useless for anything
edge-triggered (every menu/UI in any game on this engine).

Injected keys are now staged in pending_key_down/up and applied at the top
of begin_frame, before the edge loop. Real input is untouched.

Verification

• Real OS keypress, not injection: SendInput with KEYEVENTF_SCANCODE 0x2A
  produces a genuine WM_KEYDOWN with wParam=0x10; a probe latch then reads
  isKeyDown(LEFT_SHIFT)=1 (it read 0 before this change). In-game, holding
  Shift takes the player 4.50 → 9.00 m/s.
• Injection: a shooter harness drives MAIN → SETTINGS → ESC-back → PLAY
  entirely through injectKeyDown, asserting menu state at each step.

Pairs with Bloom-Engine/shooter#20.

https://claude.ai/code/session_01J1UWgMcrTNvwWeXcJ1T3Fp

Summary by CodeRabbit

• Bug Fixes
  • Fixed injected keyboard events so key-press and key-release states are detected correctly on the following frame.
  • Improved Windows keyboard handling to distinguish left and right Shift, Ctrl, and Alt keys.
  • Prevented modifier-based actions from being missed when Windows reports generic modifier key codes.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 2f0c17cd-f95e-4692-ad97-d549f448c727

📥 Commits

Reviewing files that changed from the base of the PR and between 1aedf68 and 3eb0414.

📒 Files selected for processing (3)

• native/shared/src/ffi_core/game_loop.rs
• native/shared/src/input.rs
• native/windows/src/lib.rs

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📝 Walkthrough

Walkthrough

Keyboard injection now stages events until frame start so pressed/released edges are computed correctly. Windows keyboard handlers resolve generic Shift, Ctrl, and Alt messages to side-specific keys before mapping them.

Changes

Keyboard input handling

Layer / File(s)	Summary
Staged synthetic key injection native/shared/src/input.rs, native/shared/src/ffi_core/game_loop.rs	InputState buffers injected key changes, applies them during begin_frame, computes edge states afterward, and routes FFI injection calls through the staged APIs.
Windows modifier key resolution native/windows/src/lib.rs	Top-level and embedded Windows procedures resolve generic modifier virtual keys using lParam before Bloom key translation.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant FFI
  participant InputState
  participant FrameLoop
  FFI->>InputState: Inject synthetic key event
  InputState->>InputState: Store pending key state
  FrameLoop->>InputState: Begin frame
  InputState->>InputState: Apply pending state
  InputState-->>FrameLoop: Compute pressed/released edges

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/windows-modifier-keys-and-injection-edges

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