feat: renaming, conditions, summon, and encounter controls

[arrowedisgaming]

Summary

This PR adds several features from BeastVault's planned roadmap plus encounter management improvements:

• Adversary Renaming — auto-suffix duplicate names on insert, inline rename on rendered cards, per-instance naming for multi-count adversaries
• Condition Tracking — toggle badges for 8 standard Daggerheart conditions per instance, with support for custom conditions via YAML conditions field or ad-hoc "+" button
• Summon Buttons — features with a summon field render a button that inserts the referenced adversary
• Clickable "Mark a Stress" — text in feature descriptions becomes interactive; shows instance picker for multi-count adversaries
• HP/Stress Controls — inline +, -, and clear buttons on HP and Stress rows

All changes are backward-compatible — no state migration needed, existing data is preserved.

Details

Files changed

• src/main.ts — state type extended with conditions and instanceName, ctx passthrough to AdversaryCard, Data type widened for arrays
• src/ui.ts — all UI additions (renaming, conditions, summon, mark-a-stress, stat controls)
• src/utils.ts — escapeRegex(), autoSuffixName(), DH_CONDITIONS constant
• styles.css — ~70 lines of new CSS for all features

New YAML fields

• conditions on adversaries — list of custom condition names
• summon on features — adversary name or list of names to summon

Design decisions

• Conditions are stored per-instance in plugin state (array), written directly rather than through updateCard since it's designed for scalar key-paths
• Instance names are a runtime concept stored in state, not in YAML
• Auto-suffix logic is shared between library insert and summon via autoSuffixName() in utils
• "Mark a Stress" uses event delegation on the card element, consistent with existing dice roll handling

Test plan

• Insert same adversary twice — second gets suffix "2"
• Double-click name on card — inline input, Enter saves, Escape cancels
• Multi-count adversary shows instance names, click to customize
• Condition badges toggle, persist across restart, independent per instance
• Custom conditions via YAML and "+" button
• Environments show no conditions
• Feature with summon field renders button, inserts adversary
• "Mark a Stress" auto-marks for single instance, shows picker for multi
• +/- and clear buttons on HP and Stress rows work correctly
• Horde size updates when using +/- buttons on HP
• "Clear all card state" clears conditions and instance names
• No regressions in existing HP/stress/dice/color/canvas functionality