Implement ParameterState model with echo suppression

[joaodotwork]

Description

Build the thread-safe ParameterState class that manages parameter values from both encoder input and OSC feedback, with temporal echo suppression to prevent feedback loops.

Tasks

• Implement ParameterState with thread-safe lock
• set_from_encoder(name, delta) — apply relative change, mark dirty, set echo window
• set_from_osc(name, value) — apply if not within echo suppression window
• 100ms temporal echo suppression window
• Value dead zone (0.001 threshold) to handle float rounding
• pop_dirty() — return and clear set of parameters needing redraw
• snapshot() — return current parameter values for rendering
• Support parameter paging (banks of 8)

Acceptance Criteria

• Encoder changes propagate immediately to display and OSC
• OSC feedback updates display but doesn't echo back to VDMX within 100ms
• Thread-safe under concurrent encoder + OSC updates
• Tests cover echo suppression timing and concurrent access

Technical Notes

Three-layer feedback suppression:

1. Temporal — 100ms window after local change, ignore incoming OSC for that parameter
2. Value dead zone — ignore changes < 0.001 (float rounding noise)
3. Source tagging (optional) — track last change origin