Add stable unique finding IDs for net-scoped findings

[badimirzai]

Some finding IDs are still generic or only incremented, e.g. pullup_ohms or pullup_ohms_01. Future UI version needs stable IDs for selection, highlighting, and diffing across reruns.

Goal:
Generate deterministic finding IDs based on rule + contract + affected object.

Example:
pullup_ohms_i2c_pullup_policy_I2C_SDA
pullup_ohms_i2c_pullup_policy_I2C_SCL

Acceptance criteria:

• IDs are deterministic across repeated runs.
• IDs include rule ID and affected net/component where possible.
• Existing reports remain readable.
• Avoid absolute paths in IDs.