Use test key constants

[ColonelBucket8]

Description

Currently, test files contain hardcoded key strings like "gr", "h", "<ctrl+d>" scattered across multiple files. This makes tests fragile and harder to maintain - if a keybinding changes, multiple test locations need updating.

Current usage (17 hardcoded key strings in tests)

src/tests/mod.rs

• "h" - help menu (line 49)
• "gr" - refresh (lines 315, 369, 446, 458, 474, 489)
• "jjsj" - test navigation (line 365)
• "<ctrl+d><ctrl+d>" - half page down (line 674)

src/tests/commit.rs

• "grjjjjjcF" - refresh + commit (line 22)
• "grjjjjjjjjjcF" - refresh + commit (line 41)

src/tests/editor.rs

• "jjjjkk" - editor navigation (line 19)
• "<ctrl+d>" - half page down (line 26)
• "<ctrl+d><ctrl+d><ctrl+d>" - half page down (line 33)
• "<alt+k><alt+k>" - move prev section (line 40)
• "<alt+j>" - move next section (line 47)
• "<alt+j><alt+h>" - move next + parent section (line 54)

Proposed solution

Create a new module src/tests/keys.rs with constants matching the default keybindings from default_config.toml:

// Root menu bindings
pub const HELP: &str = "h";
pub const REFRESH: &str = "gr";
pub const MOVE_UP: &str = "k";
pub const MOVE_DOWN: &str = "j";
pub const MOVE_PREV_SECTION: &str = "<alt+k>";
pub const MOVE_NEXT_SECTION: &str = "<alt+j>";
pub const MOVE_PARENT_SECTION: &str = "<alt+h>";
pub const HALF_PAGE_DOWN: &str = "<ctrl+d>";
pub const TOGGLE_SECTION: &str = "<tab>";

// Test-specific sequences (not in default bindings)
pub const NAVIGATE_DOWN_4X: &str = "jjjj";

Then update test files to use these constants:

// Before
ctx.update(&mut app, keys("gr"));

// After
ctx.update(&mut app, keys(REFRESH));

Benefits

1. Maintainability - If a keybinding changes, only update one place
2. Readability - Constants have meaningful names explaining their purpose
3. Discoverability - All test key strings are in one documented location
4. Type safety - Easier to catch typos via constant name changes