Remove redundant /abstract/ route synonyms throughout the API

[Copilot]

This PR removes all redundant /abstract/ route synonyms from the data API, addressing issue #618. These routes were serving the same documentation landing pages as their main /$resource counterparts, creating unnecessary duplication and potential confusion.

Changes Made

Removed 16 /abstract/ route decorators across 13 route files:

• Single abstract routes removed (11 files): alfresco.py, beetles.py, boundary.py, degree_days.py, ecoregions.py, elevation.py, fire.py, hydrology.py, landfastice.py, permafrost.py, seaice.py
• Multiple abstract routes removed:
  • taspr.py: Removed 3 abstract routes (/temperature/abstract/, /precipitation/abstract/, /taspr/abstract/)
  • wet_days_per_year.py: Removed 2 abstract routes (/wet_days_per_year/abstract/, /mmm/wet_days_per_year/abstract/)

Before and After

Before:

@routes.route("/degree_days/")
@routes.route("/degree_days/abstract/")  # Redundant
@routes.route("/degree_days/heating/")
def degree_days_about():
    return render_template("/documentation/degree_days.html")

After:

@routes.route("/degree_days/")
@routes.route("/degree_days/heating/")
def degree_days_about():
    return render_template("/documentation/degree_days.html")

Impact

• No functional changes: All main /$resource routes continue to work exactly as before
• Simplified routing: Eliminates confusion between duplicate routes serving identical content
• Cleaner codebase: Removes 16 lines of redundant route definitions
• No breaking changes: Only removes synonyms, doesn't affect existing functionality

All route files have been validated for correct Python syntax and the main documentation routes remain fully functional.

Closes #618

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[charparr]

The diff is all red, as expected. This seems like a reasonable, low-risk test drive of using agentic copilot to clean up a bit of cruft in the API. I'm OK with merging this.