AKUNUR 2.10.0 - ECHO PIECES AND STANDARD OPENING

Goal
Introduce the first specialist stone and remove the awkward beginner setup from the default game while preserving free placement for advanced play.

Baseline
Built from 2.9.4.
The 2.9.4 pointer/selection accuracy changes are retained.

What changed

1. Standard starting position
- New games now begin in the movement phase from a fixed 12-stone formation for each player.
- The formation is balanced by 180-degree rotational symmetry: Black's positions are the radial echoes of White's.
- White moves first.
- A Game settings selector allows players to switch to Free placement (advanced).
- Free placement retains the existing rings 2-4 setup rules.

2. Echo Pieces
- The first claim of a corner token now awards an Echo Piece rather than an ordinary bonus stone.
- Echo Pieces retain White or Black ownership but are displayed with a red outer ring and red centre.
- Echo Pieces may move normally.
- Instead of a normal adjacent move, an Echo Piece may jump directly to its Echo Point when that destination is empty.
- Selecting an Echo Piece displays a red dashed line to the Echo Point and a distinct red destination marker.
- Echo Piece status is retained when the piece moves, is captured and displaced, or is restored by Undo.
- Repetition detection now includes Echo Piece identity.

3. Terminology and rules
- "Echo Point" is defined as the cell the same distance from the Still Point on the directly opposite radial line.
- In-game rules and the printable PDF have been updated.
- The PDF includes a diagram of the provisional standard opening.

Implementation notes
- Board ownership remains stored in state.pieces as W/B for compatibility with the existing AI.
- Specialist status is stored separately in state.echoPieces.
- The standard opening is intended as a playtest baseline, not a final commercial layout.
- Echo Point jumping is non-capturing in this version and requires an empty destination.
- The simulator currently imposes no finite Echo Piece reserve while the mechanic is being tested.

Validation completed
- JavaScript syntax checks for all source files.
- Default opening contains 12 legal starting stones for each player.
- Every Black starting cell is the radial echo of a White starting cell.
- Free-placement mode still begins with 12 stones in each reserve.
- Corner reward placement creates an Echo Piece.
- Echo Point jump generation and execution tested.
- Echo Piece status through capture displacement tested.
- Heuristic AI smoke-tested from the default opening.
- Updated PDF rendered and visually inspected.

Version
2.10.0
