Remove stepCount/stepSize; patterns own their geometry

The stepCount and stepSize knobs were two controls for one quantity users
actually care about (reach), and the number of steps is an implementation
detail nobody meaningfully tunes. Each pattern has a natural size and
resolution — a jitter is inherently small, an arc a broad curve — so those
now live as constants in each strategy rather than as global config.

- strategies.ts: each pattern defines its own step count and size; MoveContext
  drops `config` down to pure geometry (start/width/height/rng), and the
  module no longer imports Config at all (dissolving the type-only-import
  cycle workaround). line stays byte-for-byte: 250 one-pixel steps.
- executor.ts: executePath takes `config` for pacing (stepDelay); the path
  itself needs nothing from it.
- config.ts / cli.ts / move.ts / config.default.json: drop stepCount and
  stepSize from the type, seed, validation, resolver, CLI flags (-n, -s),
  and help. stepDelay stays as the one pacing lever.
- configFile.ts: tolerate the removed keys instead of rejecting them — every
  pre-1.3.0 install seeded stepCount, so a hard "unknown key" failure on
  upgrade is avoided. They're ignored with a one-line stderr notice; genuine
  unknown keys still error.

The -n/--step-count CLI flag (shipped since 1.0.0) is now an unknown option;
config files degrade gracefully, command lines don't. Stays in the unpushed
1.3.0 release. 64 tests pass.

src/cli.ts

@@ -16,8 +16,6 @@
  *   -m, --move-interval     Idle time (seconds) before a sweep fires.
  *   -c, --check-interval    Cursor poll cadence (seconds).
  *   -d, --step-delay        Pause between synthetic steps (ms).
- *   -n, --step-count        Steps per sweep (count).
- *   -s, --step-size         Pixels moved per step.
  *   -p, --pattern           Movement strategy name (see strategies.ts).
  *   -V, --verbose           Enable per-sweep / interrupt / bounds logging.
  *                           (`-V` capital because `-v` is `--version`.)
@@ -48,8 +46,6 @@ export interface ParsedCliArgs {
     moveInterval: number | undefined;   // seconds
     checkInterval: number | undefined;  // seconds
     stepDelay: number | undefined;      // milliseconds
-    stepCount: number | undefined;      // count
-    stepSize: number | undefined;       // pixels
     /** Movement strategy name, validated against the registry. */
     pattern: string | undefined;
     /**
@@ -107,8 +103,6 @@ export function parseCliArgs(): ParsedCliArgs {
                 "move-interval":  { type: "string",  short: "m" },
                 "check-interval": { type: "string",  short: "c" },
                 "step-delay":     { type: "string",  short: "d" },
-                "step-count":     { type: "string",  short: "n" },
-                "step-size":      { type: "string",  short: "s" },
                 pattern:          { type: "string",  short: "p" },
                 verbose:          { type: "boolean", short: "V" },
             },
@@ -131,8 +125,6 @@ export function parseCliArgs(): ParsedCliArgs {
         moveInterval:  parsePositiveNumber("move-interval",  values["move-interval"]  as string | undefined),
         checkInterval: parsePositiveNumber("check-interval", values["check-interval"] as string | undefined),
         stepDelay:     parsePositiveNumber("step-delay",     values["step-delay"]     as string | undefined),
-        stepCount:     parsePositiveNumber("step-count",     values["step-count"]     as string | undefined),
-        stepSize:      parsePositiveNumber("step-size",      values["step-size"]      as string | undefined),
         pattern:       parsePatternName(values.pattern as string | undefined),
         verbose:       values.verbose === true ? true : undefined,
     };
@@ -176,10 +168,9 @@ Options:
   -m, --move-interval <seconds>   Idle time before a sweep fires. Default: ${moveDefaultSec}.
   -c, --check-interval <seconds>  Cursor poll cadence. Default: ${checkDefaultSec}.
   -d, --step-delay <ms>           Pause between synthetic steps. Default: ${DEFAULT_CONFIG.stepDelay}.
-  -n, --step-count <count>        Steps per sweep. Default: ${DEFAULT_CONFIG.stepCount}.
-  -s, --step-size <pixels>        Pixels moved per step. Default: ${DEFAULT_CONFIG.stepSize}.
   -p, --pattern <name>            Movement strategy. Default: ${DEFAULT_CONFIG.pattern}.
                                   One of: ${PATTERN_NAMES.join(", ")}.
+                                  Each pattern defines its own size and speed.
   -V, --verbose                   Log every sweep, interrupt, and bounds event
                                   (default prints only the startup banner).
 
@@ -189,7 +180,7 @@ Examples:
   move
   move --move-interval 180 --check-interval 5
   move -m 300 -V
-  move --pattern arc --step-size 3
+  move --pattern arc
   move --config ~/myprofile.json
 `);
 }